QWebEngineView weird rendering issues when used in combination with "libSDL" library (MacOSX)

My Qt application uses latest version of libSDL: https://www.libsdl.org to display camera preview on the screen.

When I used older versions of Qt (with WebKit engine) it all worked fine. When Chromium bakend was introduced in Qt5, my application started behaving in a very strange and unpredicted manner. Screen of the web engine view gets kind of "messed" with SDL window's content, it starts to display some weird images, rectangles etc... To me it seems like somehow the "buffer" of my SDL library gets messed up with the Chomium engine process.

So far I have tried with latest versions of Qt, libSDL, and no success.

I repeat, same code, same application and same SDL library works just fine with Qt version prior to Chromium backend (when webkit was used).

I have attached source files of the demo app, and also some images of the rendering problems.

Any direction where I should look and investigate this problem would help.

Thanks in advance.