[REG: 5.6-2->5.6.3]: Scrolling gesture inside QtQuick jumpy on macOS touchpad

Taken from https://forum.qt.io/topic/83013/scrolling-gesture-inside-qtquick-jumpy-on-macos-touchpad-video-inside:

This behaviour seems to be a little random but it happens often and is quite persistent.
When scrolling using the macOS two finger gesture the flickable area becomes jumpy.

As an example I have tested this inside the examples app "Gallery" in QtQuick Controls 2.

This happens when scrolling up and down with two fingers and not releasing. When using the gesture, but releasing fingers straight away it works fine.

LINK TO VIDEO DEMO - https://streamable.com/qwcsk

In the video I demonstrate this.

I do the two finger gesture.
I scroll by pressing mouse1 down and dragging the window (this works fine)
I scroll again with two fingers and this time it works fine.
I tested it on a 2011 macbook pro with the old smaller touchpad. Maybe this issue doesn't affect newer models. Can anyone confirm or deny this?

Can anyone replicate this glitch? This glitch goes away, but after using my mac normally like browsing the web on Safari, the glitch comes back.