[Skyblock 3] (maybe other servers as well) random hoppers stop working

IGN: Chunk_
server: skyblock 3, there may be other server having the same issue cause I've had this problem on other (not IJH servers which were on 1.9).
issue: random hoppers stop transferring items (not due to redstone etc. I know how that kinda stuff works).
You can fix it by breaking the hopper and replacing it.

Coordinates of the youtube video: 17839, 63, 36457
youtube video:

EDIT:
I came back later to discover my hoppers work again. Never the less it's still a bug.

 

This happens to me a lot on skyblock 2. I'm pretty sure it's because if some of the chunks are unloaded with hoppers, the items stay in the loaded hoppers and when you reload all chunks it messes up or something. I might be wrong but it's just my guess

 

This never happened before and this time it's literally all my hoppers on that hopper chain and maybe even more.

 

This looks to me like it's a developer bug which means it most likely has something to do with Minecraft, not the server.