I suspect your engine is still in beta stage, but i just compiled your newest source (after Commit 4ed3794) and let it play a 15 min. game in CuteChess GUI. Then this illegal move happened :

Here's the CuteChess log : cutechess-log.zip

Btw. the engine has no / poor time management, it almost lost on time.

[ i'm on Xubuntu 22.04 ]