Subscribing to communities from other Lemmy instances

So far I'm finding that subscribing to communities doesn't seem to be the same experience as actually being a participant on that Lemmy instance that we're Federated with. Notably, the upvotes don't seem to sync properly to our instance which makes communities feel dead when they have hundreds or thousands of users on other instances. Also, it feels like a lot of the posts and/or comments from other instances don't actually show up when I subscribe to those communities from our instance.

Can anybody else share their experience? Is this just an issue with our particular instance? Or a bug with synchronization across instances? Or does it just take a long time for things to catch up?

Also, the sorting is horrible. Sorting by "Active" sometimes shows me posts from over a year ago, and sorting by "Hot" seems to have similar issues. The only way of seeing newer content at the moment seems to be sorting by "New".

Hopefully a lot of these issues are resolved over time but right now it definitely feels a bit rough around the edges.