I logged in to my Shaman on Cata classic (this character), finished my JC daily and noticed my guild reputation increased despite being exalted since I finished leveling near launch. Went to check, and i got reset back to Neutral. Character did not get removed, nor leave, the guild at any point. This also happened to our shadow priest in raid a couple days ago.
Can confirm this has happened to one of our guildies as well today, second time for them.
This just happened to me too today while playing, i had turned some quests in and nothing, went to do some dailies and all of a sudden i was getting guild rep again. I looked and i went from exalted → neutral.
My paladin also had this happen to him. Went from 999 exalted to 0 neutral. Was unable to use the guild bank, the guild banners, cloak of coordination, etc.
Sent tickets in, customer support can’t/won’t do anything about it.