Start11 2.53, but same behavior existed on previous version(s) as well.   Enhanced taskbar On. Windows 11 Enterprise 24H2 26100.6584

Using a laptop, when booting to OS the first time if plugged into the a USB-C/thunderbolt dock with 2x external monitors and using the laptop display everything works fine. 

When unplugging from the dock, after giving the OS and Start11 time to catch up to the dock being unplugged, all applications that can go fullscreen maximized think the taskbar is still at the bottom of the screen instead of vertical.  So the vertical taskbar covers part of the application(s) and the bottom portion of the screen is blank to the desktop (where W11 taskbar would be).

Using Start11 menu to restart explorer.exe resolves the issue temporarily but then the opposite event might or might not happen when plugging back to the dock from single monitor, it doesn't seem consistent. 

Same behavior across all 3 dock brands I have access to so it doesn't seem to be dock or driver related as nothing else is affected (Dell thunderbolt 4,  Pluggable USB-C, generic USB-C)

example of Firefox maximized when in this state: