https://support.chess.com/article/213-how-do-i-fix-my-disconnect-lag-issues
Chrome Site Lag

The problem is not the browser you choose.
The problem is the site.
chess.com has severe lag issues.

The problem is not the browser you choose.
The problem is the site.
chess.com has severe lag issues.
Based on the OP description, it was an issue with their Chrome install, since changing to a different browser resolved the issue.
It likely wasn't Chrome specific but with a cache or an extension issue in the specific install. Or there was an update of the browser available; I have seen issues with pending updates cause the browser to have issues in websites.
I was forfeited 3 games yesterday - I was searching for a blitz game and the site was taking a while so I tried refreshing. Then I noticed in my game log I had lost 3 games. 3 games with zero moves.
The site never put me into the live server on my end and I lost 25 points. WTF ccom...
I sent in half a dozen bug reports but no one messaged me back.
Turns out it may be some issue with ccom/G Chrome? Because the site started behaving after logging into Microsoft Edge. I couldn't use simple analysis features or click certain buttons on Chrome. Very messed up.
Annoyed.