Or it could be that lag correction and disconnects were impacting the game:
Lag correction:
https://support.chess.com/customer/en/portal/articles/1444849-why-did-the-clock-times-suddenly-change-the-clocks-seem-broken-
Disconnects:
This software has wrong clock setting
Sort:
When ever I was about to win the game against player the software reduce my time so many times and increased time of few members this has happened to me so many times. Either they are partial to some players or this software or product is written by some people who don't know how to write software. It can also not be neglected that these people are over smart by giving