Other than “it’s being worked on” I doubt anyone has gotten more information.
You might want to take a look at this thread where we’ve been discussing bits and pieces we have discovered as we’ve been dealing with this back when Perenolde/Cairne was connected to Cenarius. Possibly Solved TY BLIZZ! Guild finder not working and New realm can't accept invites - #90 by Beteljuice-kargath
We believe that the issue with the guild finder and invites not being visible is related to other weird things happening with the guild roster itself. Take a look. Maybe putting our heads together, we can help give Blizzard more info and help them get this fixed.