Yes, I also had the same bug
Bug Report (Spell Chess): won the game - lost ELO

Same thing happened to me as well. There is also another topic I'd like to bring up i was against a CM, he froze his king then used his king to attack mine, then the game said it was checkmate even though i was A: Only being attacked by his king and B: Still had a freeze.

Same thing happened to me as well. There is also another topic I'd like to bring up i was against a CM, he froze his king then used his king to attack mine, then the game said it was checkmate even though i was A: Only being attacked by his king and B: Still had a freeze.
Yes, had that bug too, but I was the one who did it, checkmating the king like that
https://www.chess.com/variants/spell-chess/game/54022309/44/1
I'm white, PlausibleAlpaca. My ELO dropped from 1698 to 1688 due to this game.
Details: The website did not detect checkmate after my final move (Nxe6+) despite black's freeze being on cooldown. Instead, it detected checkmate after black moved, and announced black had won by checkmate. Screenshot of the final position:
And here's a screen shot of my new ELO, from a game I abandoned right after. This is just to prove that my ELO really did drop, and it's not just a display bug.