Cisco WLC doesn’t “like” group names with several words and space:

Therefore when you are trying to use GUI interface and add AP to this flexconnect group, it opens the group with some weird symbols (repeats 2 last):

There is no such issue with a “one word named” group.
Workaround: use CLI
(Cisco Controller) >config flexconnect group “Oriole Lane” ap add aa:bb:bb:ba:bb:aa