Under a variety of conditions, I get stuck (looks like i'm oscillating back and forth between where I was and where I want to go). In the current case w/crash report, I was standing on a stack of blocks, and it happened as I was mining the blocks out from under me.

when this happens, I can't generally mine more blocks, place more blocks, or move in any direction.

Steps to reproduce (not consistent)
1) build up a stack of blocks (jump-place) (this time it was netherrack in the nether)
2) once you're on top of the stack, begin mining the blocks underneath you
3) at some point, you'll get stuck while falling the one block you just mined. visually it looks like you're rapidly oscillating up and down.

Attaching a crash file obtained with F3-C while the condition was occurring.