I've had those same issues on the PC, but only after Hotfix 10 was implemented. (I've heard that pre-Patch4 saves will still work correctly, but can't confirm). I play for a few minutes and the UI freezes. I can still roll over player tiles in the party list, and those players are highlighted in the main viewer, but the UI doesn't seem to respond to clicks, and the party stops following. After several *minutes*, all the commands I tried to enter via the HUD seem to execute as once, but the party still won't follow. Yes, and tons of rubber-banding.
I had Halsin in my party in Rivington, and ran into the Halsin not following bug, then switched to Wyll when I hit Wyrm's Rock, to find things 10 times worse. I hear back from support on the known Halsin issue, but not on the other bugs I submitted on the show-stopping problems now inherent at least in Act 3.
So I wander for 30 seconds... and it gets unplayable again.
(I have a lot of background in software testing and some in development, but none whatsoever of either in the gaming industry. My uneducated guess as to the severity of the problem is that saves created after Patch 4 on systems that also installed the subsequent Hotfix 10 seem like they might be permanently fubar-ed. It seems like the only fix might include players rolling back and losing days of progress, which no one wants to hear.)
