BlazingBuizel (on Discord) poked me this week because they were getting this error when they clicked the validation link in their email:
Very opaque. You’d think something particularly unexpected happened wouldn’t you?
But no, what had happened is that the account had already been validated. This error message is unnecessarily opaque, so when this happens from now on it will say:
That’s all. Happy Shmepping ya’ll 
!