I don't have an M2 but still I wanted to share my experience with the unwanted shiftpoint indicator.
My car: F32 440i 2016 with ZF8 automatic gearbox. It shows the same behavior, when operating the gearbox in manual mode it makes stupid suggestions like I need to upshift from 5th gear to 7th gear while running 2000rpm.
In my case I was able to disable the shiftpoint indicator by only changing SPA_IST_GANG_ENABLE from activ to nicht_activ using Bimmercode in expert mode.
I am sharing my experience here as this thread seem to give the most complete information on disabling the shiftpoint indictator. I could not find any forumpost describing the same for non M cars.