Program freezes at start with blank window when attaching to secondary monitor

I have a computer with three monitors (one primary and two secondary). Starting up my built app so it immediately displays on one of the secondary monitors causes it to draw the app's empty frame but then the app freezes, in the sense that the UI thread crashed or hit an endless loop.

If I attempt to start the app on only the primary display (secondary monitors disconnected, then reconnected later), the app appears normally, and I can later move it to a secondary monitor without any problems. As long as I exit the app while it resides on the primary display so next startup is on primary, it will start fine.  If I close the app while it's on the secondary display and then re-run it so it auto-starts on that same display, the freeze occurs.

This is not isolated to my QT app, but happens when starting QT Design Studio (3.9.0 based on QT 6.4.0,, built Dec 14, 2022, 13:43:02, revision e91b832f33) also, so the bug seems to be in the QT window-handling core.