Yellow pieces turn grey when I go to move 1 'click arrow'

4 Player Chess - QuickCastle vs MuppetRobin vs ddc7 vs fourplayerfan - Play Chess Variants Online - Chess.com

btw the last move in the game was double checkmate. Blue mated green and yellow. Maybe it's the 'double check into resignation' type of bug from 2018, but in this case it's just double checkmate and game over (ending script) In the end blue got 20+20+1+1=42 mate mate double check pawn capture