Qt5 render issue

[Vinu]

Hi,
while trying to run a Qt application (Qt- 5.15.3) on a custom linux (on x86, kernel 5.10), we are encountering a strange problem.

This seems to be affecting only QT, and the window manager decoration seems unaffected.
Also, non-QT applications are rendering correctly.

I would really appreciate it if someone can help to identify the problem or rather give any input on this.

[JonB]

@Vinu
What QPA are you using, e.g. xcb, wayland, what? Because it looks like some driver nonsense.

[Vinu]

Thanks @JonB for the quick response.
QPA is xcb. The kernel version is 5.10. It is a custom yocto linux for linux-intel.

[Vinu]

@JonB There is one more interesting observation.
While using VNC, the same QT window is jumbled in the actual screen, while it's perfect in the VNC display.

[Vinu]

Hi,
If anyone here has any experience or knowledge related to this issue, I would be extremely grateful for your input.
Even a small suggestion or a nudge in the right direction could make a significant difference for me.