Ok, so when I was playing, I ran into a block and started suffocating and had to mine the block to get out, because the block on the same level as my character's head with no block below it allows me to just waltz into it, and I tested a couple times and you can x-ray glitch into the ground to see caves on the edge of the block. but you can only walk into them in this way after going through a nether portal, which has another bug I need to report.