Hopper minecart steeling items from higher adjacent hopper minecarts

I am Currently having this issue where a minecart hopper is "steeling" from an adjacent hopper one block above: attached is you tube video link: https://youtu.be/mhNsP4oifu4

It was discovered whilst following a tutorial for a Bedrock super smelter and occurred both before and after the 1.16.1 hotfix for player skins (unrelated but thanks for that fix)

 

I am led to beleave this is not expected behavior as was not part of any tutorial. can I please be updated if this is the case?