Some of the information in the following may help:
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
Being basic, you get advertisements, which may cause some connection/lag issues but the site doesn't have built-in bugs. There are bugs but not by design 
This chess.com has in-built bugs that will stop you from winning more games by disconnecting you from the game and you will lose ultimately. the message will appear that you have disconnected and it is due to no fault of the player's internet connection. I have experienced it many times and I am sure others have also experienced it. It is not fair play portal. I think it is time for me explore other chess portals.