Haven’t experience this in a while, but I lost when my board disconnected from a chess.com 15/10 game today. This was after getting the update that was available today (not that that probably had anything to do with it).
The specific experience - made my move on the board, which appeared to have registered - timer began counting down for my opponent. The time ran all the way to 0, and kept displaying 0, with no change once the timer was over.
When I log in to chess.com, my timer there is at 13:23, while the timer on my board is at 10:xx. It seems the board registered my move, but in those few minutes was disconnected