I've had this same problem, but it was with a single pawn (my g pawn from memory) and it was in a live chess game. Was that where yours was played? It is an odd glitch and I'm not sure what to do about it.
I lost that game in question as well, it would have been even worse without a bishop!
Rafael is a writer and coach at chess.com.
It was live. When I viewed it in the archive the bishop was on h6. Wish I had a screen grab to confirm the original weirdness
This happens to me, and what I do is go back and forth in the move history and pass over the glitchy move multiple times. Eventually it will be shown correctly.
Just happened again. Here is the proof
I just had the strangest game. Playing black, I fianchetto then move my bishop to h6. Somehow it jumped to a3 and then just sat there. I thought I could at least use the situation as blindfold chess practice, knowing that the board was not showing 1 piece in its true position, but no, the move list showed Bh6 and I found I couldn't advance the h pawn.If I tried to move the bishop I could see on a3, nothing happened and also if I tried to move it from h6 there was no result. Somehow the bishop had just been taken from the board but still occupied h6.
When I asked my opponent if he could see what had happened I got no reply, but I am sure he couldn't, since he put his Q on b4 and managed to march his a pawn straight through the bishop I could see on a3.
So I resigned, being down a full piece that I still had on the board. Even I don't usually win in that situation.