QtWebEngine Text rendering is not precise when using --single-process

When using --single-process in a webengine application, text rendering is not very precise (looks bad). See attached images. It seems that the broken rendering for some reason also has a slightly higher font weight visually.

Steps to reproduce:

• Run Qt SimpleWebBrowser sample with --single-process added to commandline
• Observe the texts
• EXPECTED: Texts are rendered the same way if --single-process is added or not
• ACTUAL: With --single-process, text rendering is ugly

Changing font engine to freetype has no effect on how the text is rendered.