Not if you sort by all. Then you see every community in every instance your instance is federated with.
It can end up in seeing the same post a lot.
Not everyone sorts by all, some people only browse on local, and so on. All things considered, I’d favor having a cool thing in multiple places to get the widest reach possible over considering having to scroll past it again a bad thing.
If you’re going to follow and interact with multiple communities, I think using the voting system to encourage good content in each one of them is a cool thing to do (especially in the Fediverse which doesn’t do shady algorithm stiff to force unrequested things in front of its users; we users are the only thing keeping the good stuff moving up to the top.)