The Minecart with Hopper have a strange bug, they send his items to another Minecarts that shouldn't receive those items because are not under the first Minecart, and more strange is that this bug only apears in some orientation (East to West) but in the orientation North to South works well. (As expected)

It looks like is related to the collision box of the Minecart as you can see in the next video https://youtu.be/XLY0cmUPD_0 because the Minecarts are moving by themselves.

Sorry for my bad English, I hope this helps you.

My phone is a GoMobile 504,