What steps will reproduce the problem?
(1) Plug an external mouse to the device.
(2) Switch to tablet mode (the device is in rotatable clamshell mode since the external mouse), and rotate the screen to make it at landscape secondary screen orientation.
(3) Unplug the external mouse. Device will enter tablet mode in this case.
(4) Switch to clamshell mode.

What is the expected result?
The screen is in landscape secondary screen orientation.

What happens instead?
The screen should in landscape primary screen orientation? (Not sure).

In rotatable clamshell mode, we can rotate the screen to switch between landscape primary and landscape secondary screen orientation. This will change the screen orientation in the settings, which means the user orientation. Switch from tablet mode to clamshell mode will set the screen orientation to user orientation. This is why the screen orientation is landscape-secondary in this case.