I'm now at 6 days (which is a new record / I've had the car for 2+ months) in which I have no radio presets reset! Have you guys looked at your profile settings? There should be a default profile, and then your profile. Fill out radio presets for both profiles and assign your plugged in phone to both (assuming you are the primary driver). Make another profile with another plugged in phone (don't know if this is possible if you don't have a work phone or maybe use spouse's phone) and set radio presets. Note to only have 1 phone plugged in at one time. I think multiple confuses the infotainment system.
Pretty sure its not a profile problem, although I thought the same at first too.
I only have 1 profile set up in my car (my phone, not my wife's).
I connect my phone via USB every time I get in (I live and die by Android Auto), and it connects via bluetooth every time.
I did not deviate from the practice prior to my FM stations getting removed, nor did anything "unusual" happen.
I'm not really complaining about it... its an inconvenience at worst, because I normally stream my music... just trying to add my experience to those trying to identify the problem.