Multi-Monitor setup keeps moving Reading Pane to Primary Monitor when Opening additional files

I have a dual-monitor setup and like to keep my primary monitor on the left and secondary on the right.  While I have the Adobe Acrobat Reader DC application open on the secondary monitor, I also have my Explorer window open to list file contents and double-click the pdf files to open.  If I close all open pdf documents and re-open one, it will retain the same position on my secondary monitor.  If I open any additional documents, it appears to relaunch Reader over on my primary monitor.  Every time.  If I close Reader on my secondary monitor and then relaunch a previously viewed document, it will display at the last position on my secondary monitor where I closed it, but then back to primary monitor for every document in addition to the first, regardless of whether I had previously viewed and closed it on the secondary monitor.

This is incredibly frustrating and I've looked through all of the various preferences, but do not see anything related to this.  I simply want to be able to place my Reader DC window on my secondary screen and open/view multiple documents without have to drag the frame back over every time.  Any tips?  Windows 10 system.