guys, calm down please.
I’ve replaced the cr2032 battery today, but the ppm remains similar. So replacing it is unfortunately not a solution. but considering the age of the appliance i expect replacement was very much due. Again thanks @Bas for your suggestion!
If we come back to the original question based on the input from @apuls i am convinced that the high-ppm value in the sync on page is not relevant.
Thanks to everyone for clearing this up!