Me too, always the bottom half like picture above, in all my chests! Logged into an old world with full chests and have now lost all the bottom halves, because I didn't realise this issue at the time; came out made a copy deleted old copy and have now lost loads of stuff!!! This has occurred since the last update.
I agree with smokeycheese13, the Ghasts seem to be the only ones that spawn way to frequently, and you kill one then within a couple of seconds another appears in it's place. I'm finding that I cant enter some places because I'm getting constantly attacked!!