Loading fonts in a Qml application results in corruption of glyphs of various languages

It seems that something can go wrong when a Qml application loads fonts. This problem manifests itself as corruption of glyphs of various languages such as Russian, Thai, Vietnamese and Czech. This is known to occur at least with Avenir font. This bug might be related to QTBUG-61984

Preparations:

• To Qt Development: Please see the comment section for instructions on how to get the complete sample project.
• To public: Open the .zip attached and complete the project by adding the following .ttf files into 'fonts' folder: AvenirNextLTPro-Regular.ttf, NotoSans-Regular.ttf, SourceSansPro-Regular.ttf

Steps to reproduce:

• Run the sample
• Click on the button "Page 1". -> Page 1 opens, the glyphs are OK. Observe the texts in various languages.
• Click on the page. -> Application returns to the starting page.
• Click on the button "Page 2". -> Page 2 opens.
  EXPECTED: The glyphs are OK. The texts in various languages look the same as before.
  ACTUAL: The glyphs are corrupted.

If you keep going back and forth between the pages the corruption effect disappears.