When I close the laptop's cover, Dell Inspiron C7486 Chromebook 2-in-1 switches from desktop to tablet mode

Steps to reproduce the problem:
1. Cover a laptop
2. Uncover one
3. You'll see that device works in tablet (not desktop) mode

Device switches to desktop mode again only after the tilt angle of 150 degrees. So I guess that Chromebook understands the covering as need to switch to tablet mode.
P.S. It's impossible to use the physical keyboard in the tablet mode. So this bug makes me to open the laptop cover for 150 degrees to use one.

Chrome OS is 77 (stable), Chrome flags are default, I don't use a developer mode. I've made a recovery from USB, but there are no results. Google support sends me to Dell support.