When you create a custom group and attempt to give it a name such as 'ad-hoc_group(3)
The POST response has a useful error message. However the UI gives a misleading error message. See attached screenshot. The UI should display the message the POST returns (ideally looked up from message.properties).
FWIW the group name I believe is valid (at least I think it is valid as a PAGS group name). However I am all for keeping the names simpler. It would also be nice if the POST response indicated the valid characters.