I’m fairly new to fediverse/instances, but my understanding that these Instances are federated with each other, so they can show the same posts/communities (depending on their respective filters).
So, why does searching for communities show different results, and even show different subscriber counts for one that do appear across all results?
Is this a case of the servers just needing to sync with each other?
You can search for a post or comment using the full URL from the other instance.
But yeah, posts and coments should be assigned GUIDs. This was probably avoided because your local instance creates the post before it is federated the the home instance of the community. There are probably some technical challenges but I can’t imagine they are insurmountable.
As an example, you could say the instance with the person creating the post should assign the GUID, but then you could have bad actor instances assign already used GUIDs to intentionally cause things to break. You could say the communities home instance should assign it, but what ID does it get between when you post it and when it’s federated to the communities home instance (it doesn’t go straight away, but is queued for background federation - which isn’t always successful)?
These are things that will likely have solutions, but it’s easy to see how the current setup came to be. It’s mich easier to manage from a technical perspective.