Are you running your generator?
If so it MAY BE that your inverter/charger or converter is set to a higher voltage than your alternator. That can cause your symptoms.
Turn off the generator and see if the symptom persists.
Even a high output solar, set at higher than alternator/regulator voltage can cause this.
Said another way, any charge source at higher voltage than alternator can cause this.
Ex: 2003 Alpine 38FDDS. Ex: 1997 Safari Sahara. Ex: 1993 Foretravel U240