Problem with my friend when he enters my map for more than once.

Every time my friend enters my map (he plays on the phone) The game starts to get weird for him, the blocks disappear and he starts to fall into the void, getting stuck in the walls as if it were a Chunck bug.
This does not happen the first time it enters the map, only when it comes out enters the map again.

Some observations:
I am Brazilian and I used a translator to pass this text to English, so I'm sorry if this text was typed incorrectly.
I play on the PC and it on the phone.
We both have the original Minecraft.