Linoone (SS 44). Sniff Out doesn't say which card from the discard pile was put into the player's hand. This is a severe problem because it means the Sniff Out Pokémon player's opponent would need to either constantly memorize the opponent's discard pile to know what was put back, or else ask the opponent what was put back and hope he can trust him.
Minun from Deoxys is a much more relevant Sniff Out Pokémon in other formats, and if it is bugged in this way too, it could have a severe impact on those formats.
------------------Begin Game Log------------------
The game is about to start
Type: QuickPlay
Format: 2004 (EXP–HL)
Battle begins between JayHornung and Evan_Cole!
Coin flip [Opening Flip]: HEADS
JayHornung will start
Game setup complete
Between turns
Turn 1 begins
Attached a [P] Energy to Root Fossil
DEBUG: Root Fossil’s Current_Energy_Cards: [[P] Energy]
Between turns
Turn 2 begins
Evan_Cole drew 1 card
Attached a [G] Energy to Corsola
DEBUG: Corsola’s Current_Energy_Cards: [[G] Energy]
Put Whismur (HL 82) onto bench.
Corsola used Coral Glow
Evan_Cole drew 1 card
Between turns
Turn 3 begins
JayHornung drew 1 card
Root Fossil evolved into Lileep (SS 42)
Lileep used Influence
Put Lileep onto bench.
JayHornung has shuffled deck.
Between turns
Turn 4 begins
Evan_Cole drew 1 card
Whismur evolved into Loudred (HL 39)
Evan_Cole played Steven’s Advice (HL 92).
Evan_Cole drew 2 cards
Attached a [G] Energy to Loudred
DEBUG: Loudred’s Current_Energy_Cards: [[G] Energy]
Corsola used Coral Glow
Evan_Cole drew 1 card
Between turns
Turn 5 begins
JayHornung drew 1 card
[Evan_Cole]: weird interaction
JayHornung played Steven’s Advice (HL 92).
JayHornung drew 2 cards
Attached a Double Rainbow Energy (MA 88) to Lileep
DEBUG: Lileep’s Current_Energy_Cards: [[P] Energy, Double Rainbow Energy (MA 88)]
Lileep used Time Spiral
Coin flip [Time Spiral]: TAILS
Between turns
Turn 6 begins
Evan_Cole drew 1 card
Evan_Cole played TV Reporter (DR 88).
Evan_Cole drew 3 cards
Corsola (HL 32) was discarded
Corsola used Coral Glow
Evan_Cole drew 1 card
Between turns
Turn 7 begins
JayHornung drew 1 card
Put Nincada (DR 67) onto bench.
JayHornung has shuffled deck.
JayHornung played Friend Ball (SKR 126).
Put Zigzagoon (SS 85) onto bench.
Lileep evolved into Cradily (SS 3)
JayHornung played Copycat (EXP 138).
Put 3 cards to Deck
JayHornung has shuffled deck.
JayHornung drew 10 cards
JayHornung played Root Fossil (SS 92).
Put Root Fossil (SS 92) onto bench.
Lileep used Time Spiral
Coin flip [Time Spiral]: TAILS
Between turns
Turn 8 begins
Evan_Cole drew 1 card
Evan_Cole played Copycat (EXP 138).
Put 10 cards to Deck
Evan_Cole has shuffled deck.
Evan_Cole drew 9 cards
Put Whismur (HL 82) onto bench.
Corsola used Coral Glow
Evan_Cole drew 2 cards
Between turns
Turn 9 begins
JayHornung drew 1 card
Attached a Double Rainbow Energy (MA 88) to Cradily
DEBUG: Cradily’s Current_Energy_Cards: [Double Rainbow Energy (MA 88)]
JayHornung played Underground Expedition (SKR 140).
JayHornung drew 2 cards from the bottom of their deck.
Lileep evolved into Cradily (SS 3)
Cradily used Lure Poison
Whismur is now active
Whismur is now poisoned
Between turns
Whismur got 10 damage due to poison
Turn 10 begins
Evan_Cole drew 1 card
Attached a [G] Energy to Whismur
DEBUG: Whismur’s Current_Energy_Cards: [[G] Energy]
Put Whismur (HL 82) onto bench.
Evan_Cole played Copycat (EXP 138).
Put 8 cards to Deck
Evan_Cole has shuffled deck.
Evan_Cole drew 9 cards
[Evan_Cole]: I have been unable to draw exploud for the last several days
[JayHornung]: seems fine to me
[Evan_Cole]: Im losing my mind lol
Whismur used Wail
Whismur did 10 damage to Cradily
Cradily is now active
Between turns
Whismur got 10 damage due to poison
Turn 11 begins
JayHornung drew 1 card
Attached a [P] Energy to Cradily
DEBUG: Cradily’s Current_Energy_Cards: [[P] Energy, Double Rainbow Energy (MA 88)]
Cradily used Spiral Drain
Cradily already has full health.
Double Rainbow Energy -10
Cradily did 40 damage to Whismur
Whismur was knocked out
Whismur (HL 82) is no longer poisoned
JayHornung took one prize card.
Loudred is now active
Between turns
Turn 12 begins
Evan_Cole drew 1 card
Attached a [G] Energy to Loudred
DEBUG: Loudred’s Current_Energy_Cards: [[G] Energy, [G] Energy]
Evan_Cole played Copycat (EXP 138).
Put 8 cards to Deck
Evan_Cole has shuffled deck.
Evan_Cole drew 10 cards
Evan_Cole has shuffled deck.
Evan_Cole played Friend Ball (SKR 126).
Whismur evolved into Loudred (HL 39)
Loudred evolved into Exploud (HL 6)
Exploud used Bass Control
Exploud did 30 damage to Nincada
Between turns
Turn 13 begins
JayHornung drew 1 card
Cradily used Spiral Drain
Cradily already has full health.
Double Rainbow Energy -10
Cradily did 40 damage to Exploud
Between turns
Turn 14 begins
Evan_Cole drew 1 card
Attached a [G] Energy to Loudred
DEBUG: Loudred’s Current_Energy_Cards: [[G] Energy]
Evan_Cole played Copycat (EXP 138).
Put 7 cards to Deck
Evan_Cole has shuffled deck.
Evan_Cole drew 11 cards
Put Treecko (DR 80) onto bench.
Evan_Cole played Rare Candy (SS 88).
Treecko evolved into Grovyle (RS 32)
Desert Ruins (HL 88) is now in play.
Exploud used Bass Control
Exploud did 30 damage to Nincada
Nincada was knocked out
Evan_Cole took one prize card.
Between turns
Turn 15 begins
JayHornung drew 1 card
Cradily used Spiral Drain
Cradily already has full health.
Double Rainbow Energy -10
Cradily did 40 damage to Exploud
Between turns
Turn 16 begins
Evan_Cole drew 1 card
Evan_Cole has shuffled deck.
Evan_Cole played Friend Ball (SKR 126).
Grovyle evolved into Sceptile (RS 20)
Sceptile has used Energy Trans
[G] Energy moved from Exploud to Sceptile
Sceptile has used Energy Trans
[G] Energy moved from Corsola to Sceptile
Attached a Boost Energy (AQP 145) to Exploud
DEBUG: Exploud’s Current_Energy_Cards: [[G] Energy, Boost Energy (AQP 145)]
Exploud used Thunderous Roar
Cradily is now confused
Exploud did 30 damage to Cradily
Boost Energy (AQP 145) was discarded
Between turns
Turn 17 begins
JayHornung drew 1 card
Attached a Warp Energy (AQP 147) to Cradily
DEBUG: Cradily’s Current_Energy_Cards: [[P] Energy, Warp Energy (AQP 147), Double Rainbow Energy (MA 88)]
Cradily (SS 3) is no longer confused
Cradily is now active
Cradily used Spiral Drain
Cradily was restored to full health.
Double Rainbow Energy -10
Cradily did 40 damage to Exploud
Exploud was knocked out
JayHornung took one prize card.
Loudred is now active
Between turns
Turn 18 begins
Evan_Cole drew 1 card
Loudred evolved into Exploud (HL 6)
Attached a [G] Energy to Exploud
DEBUG: Exploud’s Current_Energy_Cards: [[G] Energy, [G] Energy]
Sceptile has used Energy Trans
[G] Energy moved from Sceptile to Exploud
Exploud used Thunderous Roar
Cradily is now confused
Exploud did 30 damage to Cradily
Between turns
Turn 19 begins
JayHornung drew 1 card
Double Rainbow Energy (MA 88) was discarded
Cradily retreated.
Cradily (SS 3) is no longer confused
Cradily is now active
Cradily used Lure Poison
Sceptile is now active
Sceptile is now poisoned
Between turns
Sceptile got 10 damage due to poison
Turn 20 begins
Evan_Cole drew 1 card
Put Whismur (HL 82) onto bench.
Evan_Cole played Steven’s Advice (HL 92).
Evan_Cole drew 4 cards
Attached a Boost Energy (AQP 145) to Sceptile
DEBUG: Sceptile’s Current_Energy_Cards: [[G] Energy, Boost Energy (AQP 145)]
Sceptile used Tail Rap
Coin flip [Tail Rap]: HEADS HEADS
Sceptile did 100 damage to Cradily
Cradily was knocked out
Evan_Cole took one prize card.
Zigzagoon is now active
Boost Energy (AQP 145) was discarded
Between turns
Sceptile got 10 damage due to poison
Turn 21 begins
JayHornung drew 1 card
JayHornung has shuffled deck.
JayHornung played Friend Ball (SKR 126).
Zigzagoon evolved into Linoone (SS 44)
[Evan_Cole]: Interesting
Attached a [P] Energy to Linoone
DEBUG: Linoone’s Current_Energy_Cards: [[P] Energy]
Linoone used Sniff Out
Between turns
Sceptile got 10 damage due to poison
Turn 22 begins
Evan_Cole drew 1 card
[Evan_Cole]: What card was it?
[Evan_Cole]: It doesnt tell me
[JayHornung]: DRE
[Evan_Cole]: thanks
Evan_Cole played TV Reporter (DR 88).
Evan_Cole drew 3 cards
Desert Ruins (HL 88) was discarded
Whismur evolved into Loudred (HL 39)
Attached a [G] Energy to Loudred
DEBUG: Loudred’s Current_Energy_Cards: [[G] Energy]
Between turns
Sceptile got 10 damage due to poison
Turn 23 begins
JayHornung drew 1 card
Attached a Double Rainbow Energy (MA 88) to Cradily
DEBUG: Cradily’s Current_Energy_Cards: [[P] Energy, Double Rainbow Energy (MA 88)]
Linoone used Sniff Out
Between turns
Sceptile got 10 damage due to poison
Turn 24 begins
Evan_Cole drew 1 card
[Evan_Cole]: card?
Charmaster is now a spectator of the game
[JayHornung]: sorry
[JayHornung]: lileep
[Evan_Cole]: ty
[Charmaster]: Doesn’t say what it was?
Evan_Cole played Mr. Briney’s Compassion (DR 87).
Put [Sceptile (RS 20), Grovyle (RS 32), Treecko (DR 80), [G] Energy] to Hand
Sceptile (RS 20) is no longer poisoned
Exploud is now active
[Evan_Cole]: It doesnt 
[Charmaster]: That’s… actually… very problematic.
Put Treecko (DR 80) onto bench.
Evan_Cole played Rare Candy (SS 88).
Treecko evolved into Grovyle (RS 32)
[Charmaster]: Because you essentially would have to have your opponent’s discard pile memorized.
Attached a [G] Energy to Grovyle
DEBUG: Grovyle’s Current_Energy_Cards: [[G] Energy]
[Evan_Cole]: I agree
[Charmaster]: Make a bug report explaining the issue.
[Charmaster]: Or I could do it.
Exploud used Bass Control
Exploud did 30 damage to Cradily
Between turns
Turn 25 begins
JayHornung drew 1 card
Root Fossil evolved into Lileep (SS 42)
[Charmaster]: I’ll do it.
[JayHornung]: thanks
JayHornung played Underground Expedition (SKR 140).
[Evan_Cole]: Thank you!
JayHornung drew 2 cards from the bottom of their deck.
Linoone retreated.
Cradily is now active
Cradily used Lure Poison
Grovyle is now active
Grovyle is now poisoned
Between turns
Grovyle got 10 damage due to poison
Turn 26 begins
Evan_Cole drew 1 card
Evan_Cole played TV Reporter (DR 88).
Evan_Cole drew 3 cards
Corsola (HL 32) was discarded
Grovyle evolved into Sceptile (RS 20)
Grovyle (RS 32) is no longer poisoned
Sceptile has used Energy Trans
[G] Energy moved from Exploud to Sceptile
Attached a [G] Energy to Sceptile
DEBUG: Sceptile’s Current_Energy_Cards: [[G] Energy, [G] Energy, [G] Energy]
Sceptile used Tail Rap
Coin flip [Tail Rap]: TAILS TAILS
Between turns
Turn 27 begins
JayHornung drew 1 card
JayHornung played Underground Expedition (SKR 140).
JayHornung drew 2 cards from the bottom of their deck.
Attached a Double Rainbow Energy (MA 88) to Lileep
DEBUG: Lileep’s Current_Energy_Cards: [Double Rainbow Energy (MA 88)]
Lileep evolved into Cradily (SS 3)
Cradily used Spiral Drain
Cradily was restored 20 health.
Double Rainbow Energy -10
Cradily did 40 damage to Sceptile
Between turns
Turn 28 begins
Evan_Cole drew 1 card
Sceptile used Tail Rap
Coin flip [Tail Rap]: HEADS HEADS
Sceptile did 100 damage to Cradily
Cradily was knocked out
Evan_Cole took one prize card.
Linoone is now active
Between turns
Turn 29 begins
JayHornung drew 1 card
Put Gastly (EXP 109) onto bench.
JayHornung played Rare Candy (SS 88).
Gastly evolved into Gengar (EXP 48)
JayHornung played Root Fossil (SS 92).
Put Root Fossil (SS 92) onto bench.
Put Gastly (EXP 109) onto bench.
Linoone used Sniff Out
Between turns
Turn 30 begins
Evan_Cole drew 1 card
[Evan_Cole]: card?
[JayHornung]: Rare Cnady
Sceptile used Tail Rap
Coin flip [Tail Rap]: TAILS HEADS
Sceptile did 50 damage to Linoone
Between turns
Turn 31 begins
JayHornung drew 1 card
JayHornung played Rare Candy (SS 88).
Gastly evolved into Gengar (EXP 48)
Gengar has swapped a damage counter from Linoone to Sceptile!
Gengar has swapped a damage counter from Linoone to Sceptile!
Linoone retreated.
Cradily is now active
JayHornung played Town Volunteers (AQP 136).
Put [Lileep (SS 42), Cradily (SS 3), [P] Energy, [P] Energy, Nincada (DR 67)] to Deck
JayHornung has shuffled deck.
Cradily used Lure Poison
Corsola is now active
Corsola is now poisoned
Between turns
Corsola got 10 damage due to poison
Turn 32 begins
Evan_Cole drew 1 card
JayHornung wins the game! Opponent surrendered
[Evan_Cole]: gg
[JayHornung]: gg
[JayHornung]: JayHornung has exited game.
[Evan_Cole]: Evan_Cole has exited game.