Ok.. I have the workaround working. To have this working uncheck the safes for the IP8.
1. Set a layout with your channel strips assigned to the IP8. Save that as a “master scene”.
2. Save a copy of it and choose “Block all” on the recall filter except the IP8. in that scene, make the IP8 buttons “MUTE+SEL”. Name the scene IP8 MUTE+SEL.
3. Save a copy of the scene above and name it “IP8 MIX+PFL”. Edit the settings in this scene for the IP8 buttons to “MIX”+”PFL” and save it.
Put the IP8 scenes on 2 preferred softkeys on the surface.
This workaround doesn’t solve the mix follows pfl-issue, but atleast it makes the IP8 usable as a sidecart where you don’t have to double the strip assignment to the surface as well, to access the full functionality of your busses.