I have never seen that before, but it sounds like something is going wrong inside Max which relates to your dual monitor setup. Civil View doesn’t do anything specific with the positioning of panels within the UI.
I’ll have to point you in the direction of Autodesk Support for this one, because it sounds like it needs to be logged as a potential defect in Max itself.
Btw, what happens if you switch your larger monitor to become your primary monitor instead of your secondary monitor? Also, is your secondary monitor to the left or right of your secondary monitor? These things might be having an impact.