I had the game freeze on me twice today playing my Liliana deck. Both times the freeze occurred on my turn, the instant that I used her “raise dead” ability. I remembered to get a screenshot of this most recent one.

My hypothesis is that the freeze occurs due to some sort of weird interaction when returning something from the graveyard while a transformed creature is on your board. A transformed Elusive Tormentor can be seen in this screenshot, and I was trying to raise a Blood bond vampire from the graveyard. In my previous game, I don’t recall what was in the graveyard (probably a few things) but my board contained a transformed Heir of Falkenrath.
If there is anything to this theory, it should be almost trivial to reproduce with Liliana decks. Step 1- cast a transformable creature, step 2 - transform it, step 3 - discard one or more creatures, step 4 - use Raise Dead, Dark Petition or another effect to resurrect something.