Haven't written up a bug report yet as the form was acting up a bit last time I tried.
There appears to be a bug when going into act 2 with command undead active will crash your game after long rest.

Specifically what caused this for me was casting command undead on
Mayrina's husband after using Ethel's wand on him
.
I had him follow me around through the rest of act 1 with no issues.
Going into act 2 through the underdark or mountain pass worked fine up until I triggered a long rest and slept at camp.
The crash would occur right at autosave. Or right before if I disabled the autosave function.
My save was unusable for the past 2 weeks while I waited for a patch that would hopefully fix it.
After the patch last Friday I started it up hoping I could have my 30 hour save back, but no dice.
I did however notice the Command Undead effect was active and my undead companion wasn't in my party anymore.
Tracing back to the save I made right after Ethel's fight and opting not to take the zombie along fixed all my issues.

Couldn't seem to find anyone having the same problem after some searching.
Just wanted this to get some attention seeing as how it will brick your save.