I did basically the same. When I use my tazer to say rear lockers only, the issue is still there. So I'm hoping it's only the rear since there is no way to check the front only. I only bought one harness for now, put the harness on, and kept it at rear only, and still had the message.
I have had other electrical wiring issues where it threw codes, such as start stop not available where the dealer said it's a bad connection/loose wire. I'm hoping maybe that is it again, will be taking it to the dealer sooner or later.