As soon as I close a titled window, all titles disappear from all other windows. They can be restored, but it's a pain

[Montagnard11]

1. start Firefox on Windows 10 22h2. The titles from the previous session are there
2. Close a Firefox window. It doesn't matter whether or not it has a title
3. Look at Firefox windows title bars, and/or on the taskbar click the Firefox icon and look at the thumbnails : all "window-titler" titles are gone

If I don't do the following steps, the titles will be gone for good when I quit FF. To restore them right away, I do this:

4. Select a window which had a title
5. Click on the "window-titler" [t:] icon on a toolbar. The title is still there in the panel that opens
6. Click OK to close the panel
7. That window's title is back
8. Select another window which had a title
9. Select another tab in that window (NOT SURE THIS IS NECESSARY)
10. All titles are back on their respective windows