@CroShark Thanks for the tip. Unfortunately, it’s not working for me. I tried many, many times, both just pausing and restarting as well as stopping completely and discarding the exercise.
@c-d : Yes, I would wager than the issue hangs together with the firmware update, as the timing fits. I shall write to Polar support.
I received the armband in the US as a gift, but I live in Europe. So, unfortunately, there is no practical way for me to return it.