Time

Well, you have a lot of potential factors but anything from your local client and connection, to your ISP, any of the connections your traffic goes through, down to the chess.com datacenter and Live server process can play a part in it. As can the use or non-use of premoves by you or your opponent.
Clock Issues:
https://support.chess.com/customer/en/portal/articles/1444849-why-did-the-clock-times-suddenly-change-the-clocks-seem-broken-
Connection/lag causes/fixes:
https://support.chess.com/customer/en/portal/articles/1444918-my-internet-connection-is-fine---why-am-i-getting-disconnects-
https://www.chess.com/blog/News/how-to-adjust-your-live-chess-connection