Essentially I will be playing the game and it will randomly freeze. If I stay tabbed into the game, it continues to be frozen. However, if I alt-tab out and back in, the freeze is fixed and I can continue playing normally. I haven’t noticed any specific actions or areas that cause this issue and it occurs in both Retail and Classic.
As far as my own resolution, I’ve tried using WoW’s repair tool and have made sure my drivers are up to date. Nothing seems to fix the issue.
It’s possible. I think Windows uses triple buffered vsync, so alt tabbing might be forcing some kind of resync event where it switches buffering modes and/or some kind of buffer flush when it switches modes. You can sometimes observe this with the right overlay metrics it if you press start+g to open up the gaming overlay or if you press a volume button and the little slider shows up on the screen.
Either way, I’d give those hotfix drivers a try. Also make sure your Windows is fully up to date.