Turn 1 Supporter is legal in the SUM-LOT format, change wasn't made until Sword and Shield era. Please adjust accordingly. Thanks!
------------------Begin Game Log------------------
The game is about to start
Type: QuickPlay
Format: SUM–LOT
Battle begins between StarshineSimon and JamesG!
Coin flip [Opening Flip]: TAILS
[JamesG]: hello friend
JamesG will start
[StarshineSimon]: Hi buddy! <3
JamesG will take additional mulligan(s) after StarshineSimon sets up to play.
Mulligan phase: JamesG took 1 additional mulligans
StarshineSimon drew 1 extra cards.
Game setup complete
Between turns
Turn 1 begins
JamesG drew 1 card
JamesG played Nest Ball (SUM 123).
JamesG has shuffled deck.
Put Blitzle (LOT 81) onto bench.
JamesG has shuffled deck.
Mt. Coronet (UPR 130) is now in play.
Put Blitzle (LOT 81) onto bench.
Put Nincada (LOT 29) onto bench.
Put Ditto Prism Star (LOT 154) onto bench.
[JamesG]: are you serious
[JamesG]: i can't supporter lmao
[StarshineSimon]: lol
[StarshineSimon]: fr
[StarshineSimon]: ?
[JamesG]: yep
[JamesG]: have sightseer in my hand
[StarshineSimon]: It's been working every other game I've seen
[JamesG]: says cant play a supporter turn 1 in this format
[StarshineSimon]: bug report time :P
Between turns
Turn 2 begins
StarshineSimon drew 1 card
[StarshineSimon]: i will draw pass
Between turns
Turn 3 begins
JamesG drew 1 card
[JamesG]: appreciate it
tfw is now a spectator of the game
[JamesG]: 1 min to report the bug