End Gateway Bug.mp4
Note the video has been edited to fit the 10MB limit and to show the bug better

This is probably related to MCPE-66061, but I don't think it's a duplicate so I'm posting this here.
However, this is most likely a cause of MCPE-40538.

Me and my friends were on a world together, but I wasn't the host so that could've had something to do with recreating the bug. I threw an ender pearl and it these things(from what I could tell from my recording):

1. An endermite spawned
2. I got stuck in the gateway(MCPE-40538)
3. Phase through the gateway
4. Phased through the endermite and the ground below.

This happened a couple more times, but the endermite didn't spawn those times so I don't think it's that.