QtQuick component sizing breaks when moving window between screens of different DPI

There are various problems with the scaling of QML components when moving a QtQuick window between a low-DPI and a high-DPI screen. It can be observed with just about any QML example if the AA_EnableHighDpiScaling flag is set, so I have attached a GIF demonstrating the bug with a single button in a QtQuick window. The 100% scaling screen is on the left, the 200% scaling (4k) screen on the right.

If AA_EnableHighDpiScaling is not set the similar kind of scaling error does not occur.

Possibly related: calling setMask() on a QQuickWindow does
not update the mask size when changing the DPI scaling of a screen from 100%
to 200% or back, so the mask coordinates are not adapted to the new window
size, but the rest of the window content is.

Example attached. If "TestWindow" is replaced with Window in it and it is moved between low-DPI and high-DPI screens the scale effect can be noticed.