Couple of suggestions.

If you have been logged in for awhile then restart the client. It is a Beta so assuming a memory leak is not a bad idea.

If you get into a bad firefight, multiple vehicles and rounds every where you look, lag will result. However, not the slide show type where you get an image every second or so.

Getting disconnected and some of the lag can be addressed by making sure your ports are open (see discussion on first page of this Forum).

If someone in the squad had significant lag problem they must restart the client. In my experience it seems to just make it worse the longer they stay running and it makes it worse for the rest of a squad. That could be wishful thinking on my part.

Don't forget to either have them Leave Squad or boot the restarting gamer out of the squad first then re-invite when they are back. Not doing that might cause weirdness with the squad being partially functional.

My last caution is make sure everyone agrees not to be in any menus, fitting suits, shopping in the market or checking mail when the Squad Leader starts the Battle Finder. I used to do that and since I quit my lag issues have dropped significantly. Again this might be wishful thinking.