Renaming kerns to kern groups doesn’t work well. For example, I have kerns with c-deva on the left and other glyphs on the right. I need to turn c-deva into a the group @c-deva. If I try to do this the group becomes “@ @c-deva” and the kerning doesn’t work. But sometimes it works if I close and reopen the file after changing the group name—the group becomes @c-deva. I discovered this accidentally because renaming groups tends to crash Glyphs. I can use Tosche’s copy/paste script to copy the kerns to a new group without renaming, but I get the impression that just renaming would work if the process wasn’t hampered by multiple bugs.
Edit: closing the file after naming does not always work. One of three things happens, and which one happens seems to be random:
1 - The new group name takes effect
2 - The group name is now @@group instead of @group
3 - The group name remains unchanged.
Edit: when it seems like an @@ group is now just an @group the name can change back to @@ when opening the file again.