The game tends to crash when rapidly changing means of transportation (saddled pigs, minecarts, boats ). I noticed it first in survival when using a minecart elevator and reproduced it a few times in creative as well. The crash screen mentions an exception in world tick.

How to reproduce:
It usually requires quick changing in transport and often a few times after one another. It doesn't require the same means of transportation to trigger a crash, quickly swapping between e.g. boats and minecarts triggers it as well. However quickly getting in and out of the same means of transportation doesn't cause a crash.

Results in:
-(most of the times) A crash if done quick enough. Changing transport slowly tends to work most of the time. The transport involved in the crash sometimes disappears entirely.

-(sometimes) No crash, usually when you change transport slowly, but it can result in being 'stuck' in a sitting mode (can be observed in third person). This means not triggering pressure plates, not being able to use other means of transport...