I feel your pain @Dezthe.I have also been having the same problem with my Model S P85 (2014 model) since the start of 2021. It went in to Tesla but the situation was not resolved and they appear to be blaming the wall charger (a Rolec Wallpod), but I have never had a problem with it previously and if I force the charge to start then it charges at 32A with no problem.
I have done various tests on scheduling a charge at different times of the day. Curiously if the scheduled time is the same calendar day and less than 120 mins from when I connect the tether, then it charges at 32A but if the time is over two hours it always, or in the next calendar day, it charges at 16A.
Mine was never resolved, I just learned to live with it as we weren't doing much mileage anyway. In the event I replaced my car with a M3 which charges perfectly happily on a timed charge, using the same "faulty" WallBox charge point. Big surprise (not).