Webkit visual artefacts in some documents

[sanel]

In some docs (e.g. Java SE 11), when you scroll it, there can happen visual artefacts (image 1), but when you re-scroll it (e.g. redraw happens), it will be rendered OK (image 2). Image 3 shows after Zeal window was minimised then raised (scroll would re-render if fine after that).

I assume this might be due to a hardware acceleration in webkit. Is there any way to pass webkit or qt specific flags from command line to Zeal? This is how is done in qutebrowser.

This didn't happen in the previous Zeal versions (e.g. 0.6.x).