This has happened a coupla times to me now in the P-39Q. I'll safely ditch, lose some parts,etc - after I stop skidding, I go to external view to check out the damage and WHAM! I'm back in the tower with a message that says I have been killed.
I've ditched plenty of times in the '39 and its got a good strong airframe. Think something may have changed in recent versions/patches?