Hey I got something on this!
I went to LKQ this week and got a wiper relay for peanuts from a 300D. I decided to try to swap it into my car. Guess what? No more crazy wiper ghost. It is normal now. I can start it, stop it, honk the horn, move the mirror and the wipers don't act possessed.
The relays look different. The one with the red (my mark with a sharpie) mb logo is the old crazy one. The functional one is on the right.
I accidentally grabbed the heated window relay on the same car a week ago. I came home and realized it wasn't the wiper relay. The Pelican DIY on the wiper relay is really messed up...it calls the window defrost relay the wiper relay in the how to. I got it mixed up after I saw that.