Found this while working on QTBUG-113040.

QQuickItem::itemChange() with QQuickItem::ItemDevicePixelRatioHasChanged change is triggered with a wrong value.
Not reproduced with Qt 6.5.0, so it's regression came with some recent change on Dev.

To reproduce the problem you need environment with at least 2 displays with different scale factors. e.g. one with 100% and another with 125%.

Run attached sample project dpi_issue.zip on a display with 100% scale and move the window
on a display with 125% scale and vise versa. Check the output - you'll see that wrong (previous) DPI value is printed.

The problem exists at least on Windows, but probably it's relevant for other platforms. like macOS.