You Won! Game abandoned - Opponent has 16 minutes left

I was playing a 30 minute rapid.

I had 24 minutes left

My opponent had 22 minutes left

I got a 1 pawn upper hand in an exchange with another pawn capture difficult to avoid for my opponent.

My opponents clock ticked down to 16 minutes

Then a popup said

'You Won! Game abandoned'

I was in focus mode so I was not seeing any messages about whether my opponent had idsconnected or not.

If I am not in focus mode I see frequent messages about opponents disconnecting and reconnecting a lot of the time so I am not sure if this is related to the game abandoned result.

When I turned off 'focus mode' at the end of the game there was a message saying the opponent had disconnected but I am not sure how long after their last move that this happened although I guess it is the reason why the server declared the game abandoned (?).

I play on the PC not on my phone and my browser is permanently auto-logged in to chess.com so I am not even sure how a player is able to 'disconnect'. Does that mean they were playing on the phone and closed the app or switched the phone off?

I sometime see messages saying I have disconnected during live play so I guess the server pings the client regularly and if it does not get a reply due to network traffic congestion it is treated as a disconnection (?)

If a player disconnects is there a time limit for them to reconnect before a 30 minute live game is lost due to 'abandonment' ?

It just happened again.

This time I was not in focus mode so i was able to see messages from the system about opponent disconnection.

My opponent disconnected and the server said they would be auto-resigned in 2.00 minutes with the countdown visible.

When the clock got down to 0.30 seconds remaining the server message popped up 'You Won! Game abandoned'

Seems to just be the message for the auto-resign feature working - although curious that the win came 30 seconds early.