Windows 10 FCU
I've discovered this shocking design flaw after spending a few hours scratching my head as to why some of the assigned hotkeys does not work. In my case, transform gizmo planar constraint triggered by holding down Shift key has stopped working. It appears that the Blender decides execution priority of a shortcut based on its order in the list, so if you for example remove view3d.manipulator entries in 3D View (Global) category, and then add these very same entries with very same settings at the bottom, then Planar Constraint mode of manipulator gizmo will stop working, because some other action above will have higher priority.
Aside from being nearly impossible for the end user to figure out why this is not working, as there is no implication of this mechanism, what's even more scary is that hotkey editor in Blender does not allow for re-ordering of assigned hotkeys, so if you add a new hotkey entry, it's always added at the bottom, and only way to fix this is to open exported .py key configuration file in a text editor, and manually edit the order there.