Possible false messages from the Mercedes-Benz App

Hello EQS connoisseurs! The Mercedes-Benz app keeps telling me that the 12 V battery is almost empty. If I measure the tension on the battery with a professional device, then the usually Übr 12 V, only one measurement returned 11,87 V. In the car I have received only once a warning. Since these measurements became too cumbersome for me, I have a voltage monitor connected directly to the battery and that provides the voltage, the charging state and the temperature. There is a quite up and down there. the values. (picture) Could my charge controller be defective? Could the app give unnecessary warnings? Greetings Maria