I've just encountered this same issue. I too have 4 secret entrances from trying to move it from 1 room to another. 😞 I've exited and come back in, but I am stuck with 4 entrances. I guess I need to give it more time for them to "turn into" the vanguard portals like what happened to moosenoise. However, I really had hoped there would be more info on this topic and potential fix other than "waiting it out" and hoping the next time I try to move the entrance, it doesn't happen again.