Hi,
Garmin would not be Garmin if they had a decent software developing process, so of course with every new firmware, including the new V6.20 they introduce new annoying bugs.
If pressing long the light button for reaching the radial menu, the light is activated also. Normally it should be entered without activating the light, which is done by SHORT pressing the light button.
More on this in the Fenix 6 part of the forum :-)