If you see the image closely, the computer now has 3 bishops. The captured bishop(white) returns(at D5) somehow and is added as black. Is this a bug?
Also, the captured pieces shown on the right side of the board seems wrong.
Sounds like you are playing the "Crazyhouse" variant.
Yes. Thank you.
I am new to chess and got scared by this move.
You're welcome.
FWIW, the version of Chess on Big Sur is difficult no matter what the setting for some reason. If you are just learning Chess, you may want to try an easier version. One option would be the free online version of Shredder.
Bug in the chess app. Captured piece returns
