HighDPI: Using QT_SCALE_FACTOR_ROUNDING_POLICY=PassThrough with fractional scaling yields cosmetic issues

My setup is as follows:

Windows10
Monitor 1: 3840x2160 resolution, 150% scaling
Monitor 2: 1920x1200 resolution, 100% scaling

Using the QT_SCALE_FACTOR_ROUNDING_POLICY=PassThrough causes issues on both monitors. Mostly it has to do with rendering/painting of simple widget controls. I ran into these issues while using the Assistant and Designer applications. The issues include the following:

1. Focus around QLineEdit controls (see attachment)
2. Hovering over QPushButton controls (see attachment)
3. QCheckBox is bigger than it needs to be (see attachment)
4. Checkmark in a QCheckBox looks fuzzy (see attachment) (on both monitors)
5. Arrows in QComboBox controls looks fuzzy (see attachment) (on both monitors)
6. Fonts on the native QFileDialog do not respect scaling (see attachment) (on both monitors)
7. Designer MDI Child window's close and minimize buttons are not properly resized when the application is moved from Monitor 1 to Monitor 2

After more testing, it appears similar issues exist with rendering controls when using Ceil, Round, Floor and RoundPreferFloor values for QT_SCALE_FACTOR_ROUNDING_POLICY. Also, turning on the "Fix scaling for apps" option on Windows 10 causes additional scaling issues.

Monitor Output from qtdiag.exe

Screens: 2, High DPI scaling: active

1. 0 "\\.\DISPLAY3" Depth: 32 Primary: yes
   Manufacturer:
   Model:
   Serial number:
   Geometry: 2560x1440+0+0 (native: 3840x2160+0+0) Available: 2560x1409+0+0
   Virtual geometry: 5760x1440+0+0 Available: 5760x1409+0+0
   2 virtual siblings
   Physical size: 600x340 mm Refresh: 60 Hz Power state: 0
   Physical DPI: 108.373,107.576 Logical DPI: 96,96 (native: 144,144) Subpixel_RGB
   High DPI scaling factor: 1.5 DevicePixelRatio: 1.5 Pixel density: 1
   Primary orientation: 2 Orientation: 2 Native orientation: 0 OrientationUpdateMask: 0

1. 1 "\\.\DISPLAY2" Depth: 32 Primary: no
   Manufacturer:
   Model:
   Serial number:
   Geometry: 1920x1200+3840+0 Available: 1920x1170+3840+0
   Virtual geometry: 5760x1440+0+0 Available: 5760x1409+0+0
   2 virtual siblings
   Physical size: 518x324 mm Refresh: 60 Hz Power state: 0
   Physical DPI: 94.1467,94.0741 Logical DPI: 96,96 Subpixel_RGB
   High DPI scaling factor: 1 DevicePixelRatio: 1 Pixel density: 1
   Primary orientation: 2 Orientation: 2 Native orientation: 0 OrientationUpdateMask: 0