While it may not be a bad thing and not cause any real problem I have had reports that it's a bug from my customers simply becasue it looks odd and it does behave differently than Microsoft products that use a ribbon.
If you feel you need to maintain this popup style positioning, could you also offer an option to drop it down alligned with the parent window. Note that it appears that office products only get the window width remaining on the left most monitor the window is on. This would be ok, I think it would make even more sense for the Ribbon dropdown to use the entire parent window width and span the monitors, this would be the most natural looking.
I tried this with 2013.2 0591.
Best Regards,
Ken