Player keeps going through blocks.

There is an issue where you go through blocks, but when it happens, it happens at random and the block are floating. for example, if you make of field of any block and cover that field in carpet, then place blocks on top of it, you'll be able to go through the blocks on top of the carpet. The going through the blocks then causes game to act like your stuck in a sand or gravel block. You're essentially suffocating inside a block your not supposed to be. I hope this description is clear enough, but if not, that's ok. This is not easy one to explain. Thank You