Wizard with modern style + stylesheet paints (very) wrongly

Steps to reproduce.
1. Run the attached example.
2. Press next
3. Press back
4. Notice that the white background certainly is not matching the style sheet.

It is not clear exactly what causes it. Without trying to remove it, I (strongly) suspect the setAutoFillBackground(modern) could be a part of this issue, but there appears be more to it as autoFillbackground doesn't normally cause this behavior.

It also requires a subTitle to be reproduced.