To everyone going against building walls: it's a work-around, to stop your mobs etc. from disappearing until this bug is solved, not a permanent solution.
I want to second this issue.
I get a lot of crashes too. I will say much more often that 3-4 times a session, but my sessions have been long the last few days.
But after each crash creatures are missing. Captured sheep and cows are easily replaced. But horses, named and geared up, were kept for they colours, donkeys are found less, and it takes a bit to get a tame fox.
I'm not playing anymore until this is fixed.
This seems to have resolved itself. Typically right after I posted this issue.