I have the same issue. I thought this was supposed to be fixed.
I am within the rules, I have one personal and one FC house on my account (we are trying to relocate the FC house). The owner of the personal house can place a bid for the new FC plot but my alts are all locked out from the bidding.

I don't know what to do. I would be prepared to drop the personal house if necessary, but I'd be scared to do so without confirmation that it would actually solve the issue.