Yes I found something similar.
Here is how one can reproduce.
Macbook Pro laptop. JRMC19. External display (HDMI).
System preferences are set so that Displays->Arrangements does NOT have display mirroring on.
Drag JRMC19 over to the external display.
Issue #1 - if one chooses to re-size the JRMC19 window (green button, top left window), then the window pops back to the primary display on the Macbook Pro.
-or-
Drag JRMC19 over the the external display.
Issue #2 - the menu options are essentially non functional on the external display, they are greyed out, and basically the working controls are over on the Macbook Pro laptop. Beyond that some quirky behavior on where they are located on the Macbook Pro at that point.
I did test some other applications such as Google Chrome, and Safari and they work as expected. You can re size windows on the external display, and the menu functions are on the external display and work properly.
Barr