Move erased from a game (going backwards)

In this game:

White had already played P13. I went into analysis mode, and while clicking through variations, I somehow ended up seeing a “submit move” button. After clicking it, (I’m not sure whether I was on Black Q12, or the followup move), I ended up in the current situation. I see Q12 as the most recently played move.

Attaching a screenshot, in case it’s helpful to see the current board position after the played move has disappeared.