I’ve been encountering an increasing number of links which “may not available on your instance”, even for posts which I know are available on my instance.
Here is a absurdly silly example where I used a remote link to one of my own posts. It can’t be unavailable on my instance, because I made the post! :)
Happens very much to me, too. I’m on the latest stable build. But this has been happening for quite some time. Most of the instances are federated and I can follow these links via the web ui, but the app refuses to load them