Merging contacts does fail because of help center membership

Merging contacts does fail because of help center membership

I'm trying to merge two contact records (they are the same contact) where one of them is a member on the help center. The system warns me about this situation and then I de-activate this contact as an "End User" for the help center. Right now the system doesn't allow me to merge the contacts where even both of them are not members in the help center.