I've played multiple worlds, some over 100 hours (I like this game...) all in survival. I've tweaked the settings each time to try something new. In the world that has this bug, I added the sideways gravity (like in hardcore survival) and made the world smaller. Otherwise it is the same as other worlds I've played successfully.
The first time this happened I was chopping a birch tree. When it broke, nothing fell - the blocks just all disappeared. I could no longer pick up anything, and any block I would try to break would just disappear. I couldn't eat (it would just chomp endlessly) When I exited and reloaded the game I went back a little and time andI was standing in front of the unchopped tree, but the same thing was happening because I chopped the tree and it just disappeared. I exited then ran it in repair mode, exited, then reloaded with the same problem presenting. I exited the game entirely, restarted and loaded the world, and the same problem.
So, I created a new world with the same seed and settings. It worked for about 90 minutes. Then I was digging up some dirt with a shovel, when all of a sudden the dirt just stayed on the ground and wouldn't enter my inventory. Any new blocks I would dig would just disappear - basically the same situation as before. I am playing the 13.4 stable. Any thoughts?