Descent MK2 rebooting in Strength activity after first workout set

After the new firmware upgrade (20.40), my Descent MK2 has started rebooting in Free Strength Activity. It reboots after the first set (right after pressing the lap button). This happens almost every workout, but not always.

Any idea this is sw or hw issue or what could be done with it? (Hope this doesn’t happen during the dive).

Thxxxxx and best regards,

D.