I activated the Steam key for the Early Access, but had chosen GOG for my final copy. I've been checking my Larian Vault KS backer page every day, and I still have the red banner telling me to check back later if I want to change my Steam key into a GOG key.
I still have that too, despite having created a GOG key after deleting my Steam one.
Have you got any link under there? A small text one, along the lines of "delete this key, it's undoable" or some such?