A defect in Diode D14 or other part leaks voltage from the battery back to the charging contacts where the dock voltage is measured and reported over USB.
Selecting the "Shut Down" option on the LCD menu when stopped shows the error message, it cannot shut down when on the dock -- even though off the dock. The voltage makes a false indication.
So the unit navigates to its starting point in front of the dock and then concludes prematurely it is already docked. The software is too simplistic, ignoring the lidar etc.
This diode has been replaced in some cases where the unit will not run because stuck in charging mode, from false indication.
The diode is under-specified and can be damaged by heat. A large TO-220 package with heat sink is preferred, e.g. MBR735.
par 
