This just happened to me in a 3/2 arena game. I sat there waiting for my opponent to move then got the game abandoned notification and all the sudden his last move appeared on the screen. https://www.chess.com/a/2pHwt9La2YzEA
Second time it happened to me and I find it incredible frustrating.
I strongly believe the rules could be improved. Today this happened to me on a 10 minutes per side game and my clock didn't advance 60 seconds, it was only around 30, but my disconnection started during my opponent's turn. I strongly believe the disconnect time rule should consider only the time lost during your own turn, especially if this was thought as the maximum amount of time chess.com wants people to wait for their opponent if a disconnection happens. If you disconnect and the time taken into account is the one during your own turn, then the maximum amount of time the opponent has to wait is the same!! Because the opponent did not have to wait at all while he/she was thinking, that is not waiting time!! There is absolutely no change in the max waiting time if chess.com changes that. Likewise, it gives a much better chance for players to solve the issue as they many times will also have a % of the opponent's thinking time (which, as mentioned, is not waiting time for the opponent). As how the rule is right now, 50% of the time people don't have to wait 10% of the base time, but less, because there is a 50% chance the disconnection will occur during the turn of the player who did not disconnect.