The dealer needs to run their standard battery diagnostics plus check the charging rates so plan to bring the car in half charged. This will check the battery and the actual charging rates.
For me, the software gliche was switching to a lower charging rate automatically for some unknown reason. The service advisor said I had switched it on the dash. I replied that I had no idea where the menu was so I did NOT down throttle the setting.
Separately, I had seen a post where the charging apparatus on the car was compromised. Also, we have seen some rare cases that the inverter, etc was damaged by leaking coolant.
These are all things that MB is aware of, even if your local MB shop had not.