Anybody else has this issue? It's extremely annoying, and I can't find anything about this being an issue.
I had this issue too. I put in a bug report and a ticket. I was able to fix it.
I was in my guild on my first character, my thief, and clicking 'Represent' on my Ranger was doing nothing. I quit the guild completely and when I was reinvited, I still couldn't click join...so I declined the invite and logged back to my Thief and had my GM reinvite me -again-. I was able to click join again and able to click represent on my Ranger as well. I'd try that process until they fix it.
For anyone having this issue, seems like going to the Heart of the Mists and click "Join" there helps. It least it did for me and a few more cases I know of.
i had this issue last night, eventually fixed itself.