Anyone else have issues after security update this morning?

[fredrenner]

This morning there was a 'Restart' icon on my taskbar, presumably indicating an auto-installed security update. Business as usual -- so I thought. After restart all my display windows/fonts/icon sizes were haywire. Some text was native 4k too small to read, other text in same window at least 8x that. Konsole occupies 1/4 of the screen for 80 char by 16 lines. Writing this in Brave-browser similarly bloated. All system- and user-level display multipliers (that I know of) are set to 1. I do seem to recall that some active/inactive settings should be blank but do not remember which ones. Dolphin is one of the programs with huge window and tiny text, making the search for my notes from the last go-round with HiDPI scaling really unpleasant. What changed?
[HP Z840, nVidia, X, kubuntu 24.04 up to date, Plasma 5.27.12, QT 5.15.13, 4k display]

[fredrenner]

Not a real answer but this bit of voodoo made some progress. Making QT_AUTO_SCREEN_SCALE_FACTOR blank in ~/.profile made QT applications fall in line. Something else is setting it to '0' but it works, where my setting it to '0' did not. Still no joy on anything GTK-flavored.