I just got this version today. I'm not 100% sure of when this occurs, but the game seems to crash when I start mining down sometimes. When I load the game back up, some progress gets lost and if I was using a custom skin, it resets. 

Some occurences of the crash was when a little bit after I got to stone level, I mined a block and it crashed (one being stone and the other being gravel) and a third time I spawned on top of a tree and started to mine the stump and the game crashed.

Edit: It's any block, I'm about to mine it and it crashes the game.

Edit2: Not sure if this helps but here's the event log error:

Faulting application name: Minecraft.Windows.exe, version: 1.12.1.1, time stamp: 0x5d60603d
Faulting module name: Minecraft.Windows.exe, version: 1.12.1.1, time stamp: 0x5d60603d
Exception code: 0xc0000005