Minecart gets stuck randomly (powered on powered rails)

I completed my slime farm earlier today and I have noticed my minecarts with hoppers getting stuck randomly. I don't really understand what the hek is goin on, but it's definitely not working as intended.

As extra information: I created this world in the first snapshot of 1.16 and has been in every single snapshot that has been brought out thusfar on the server version of Java. 

 

Edit: After a bit of trying I found out that a spectator account can stop a minecart. But I feel the minecarts already got stuck before i went through the rails with my spectator account.