WYPS: two moves of one player in a row?

Can you explain what happened in this game:

https://www.littlegolem.net/jsp/game/game.jsp?gid=2173163

I play WYPS for some time, but have not seen such a thingy. Basically, the opponent had two moves in a row. Feature or a bug?

I restart it.

O...! Dakujem pekne! :)