Title expansion for StackApps links in user profiles works on MSE, and on StackApps itself, but nowhere else.
Also, on SE, it depends on where you copy the profile from. For example when copying it from SO:
But if it's copied from MSE it copies the expanded titles as well. (Note: I originally edited my profile on MSE and saved to all communities; so I can confirm that expanded titles are not copied elsewhere and the source site doesn't matter, the copy behavior is just a unique SE thing.)
StackApps title expansion should work on all sites (all the other sites' titles expand properly everywhere).