I have an old game that I run in compatibilty mode with the option to run in 640x480 resolution checked.
My Nexus dock is locked to my 2nd monitor at the bottom edge.

When the game exits, the dock moves to the primary monitor and I have to go to Screen Position and move it back.

This happens because the dock is actually being too smart for its own good: when the game switches resolutions to 640x480, screen coordinates for the secondary monitor change as well. The dock does not know that this screen resolution change is temporary, so it automatically moves itself to the new coordinates used by the secondary monitor (otherwise it would be off-screen). At this point it is still attached to the secondary monitor.

The problem occurs when the game exits and the resolution is changed back to what it was, because the dock coordinates now lie *inside* the primary monitor, and now the dock thinks that is where it belongs.

I'll see what I can do.