The system shuts down by default when the on/off switch is briefly pressed. This setting can be changed via the operating system. Proceed as follows:

  1. Open the "Power & sleep settings" (e.g. via Settings and search for "power"):

  2. Select "Additional power settings":

  3. Select the menu item "Choose what the power buttons do".

    The default setting "When I press the power button" is shut down and "When I press the sleep button" is do nothing.

  4. Also select "Do nothing" from the drop-down menu for the power button.

  5. Finally, save the changes.

The default function of shutting down when the on/off switch is briefly pressed is now disabled.