Interaction among platforms is hard I think because they each operate with different actions and elements. But even within platforms can be buggy for me, or possibly I just stumble upon restricted access, not sure. But some profiles on mastodon instances will show zero or limited content, when I know there’s more there. For example I don’t see many toots from .ie on my .social account for some reason. And some Lemmy subs will show zero or limited posts when I search them in the same way. The good thing is that this stuff seems to be being worked on constantly with all of the attention it’s gotten recently.