YES I SEARCHED FOR THIS, I SEARCH ALL THE TIME BEFORE REPORTING BUGS, DONT GIVE ME ANY OF THAT

So basically, if you travel more than 2^22 blocks from spawn in any direction, block physics start to screw up and blocks become sometimes solid and sometimes not. You can stand on the blocks normally sometimes, but moving will cause you to fall through the ground. After 8388608 it's pretty much a guaranteed fall.