...You can crouch dash?

Thank you, the lack of an @ symbol was the problem! I'd tried it without the exclamation point but hadn't tried substituting an @ symbol. And it seems like the link to it from my reddit instance didn't actually exist until I managed to get to it form the search bar.

I can't see any posts in the community from kbin for some reason, though -- do communities federate separately from instances as a whole?

Yeah, I assumed it just needed to sync, but wasn't sure because I'm definitely not the first person on my instance to sync with lemmy.world and didn't know if magazines synced independently from each other.

Interestingly, I subscribed to two magazines on that instance yesterday, and one of them is no longer empty while the other still is, 20+ hours later (and it does have posts when viewed through lemmy.world, just not through my kbin instance). Certainly takes its time, lol.