Is it Flash that disconnects?

Lost two games where I was several pieces ahead for "Interrupted Connection". Both Chrome and Opera. Nothing streaming or anything like that in the background, and I have a powerful computer (Mac, 16GB RAM, etc.).

I notice the site uses Flash. Which is not a great piece of software. Is it disconnecting? Do my opponents know a secret code that disconnects me when I am winning?

This is too frustrating. No good answer will mean going to another chess site.

The site only needs Flash for videos so you should block it from loading here until you need  it   (unless you are on v3 which doesn't use Flash at all but should still be blocked from loading). I've seen other topics where Flash has caused issues.

Now I have another idea: is it possible after a while Comcast throttles chess.com?

I guess it is possible but the amount of traffic generated by the site, probably isn't enough to cause that. I would lean towards other processes on your system being the most likely culprit.