when log out then back in, I suddenly am in a new place and die, unable to find my stuff as location unrecognizable

I log out completely, then log in as usual.
I suddenly find myself in an unfamiliar place, I get blown up presumable by a creeper I do not see, and then cannot find my stuff as it is not in the place I was at when I logged off.

a few times this happened and I was not blown up.

I think it typically happens when I am deep underground. Then I suddenly find myself on the surface in a random place.

I expect when I log out, I will be in the same place I left.

Steps to Reproduce:
1.underground
2. log out
3. log in