Here is a video of he issue (Only used tooltips but the same happens when opening any application):
https://streamable.com/1i7sk

When opening a new windows or a tooltip in a maximized window, it does flick before appearing. If you do the same with the windows no-maximized, even if it cover all the screen, it doesn't happen. Also doesn't happen if you do it when the focus is on another no maximized window (Like the last example on the video)

I am using Arch Linux with OpenBox and Arc Theme. GPU is a RX 480 using AMDGPU drivers.
I have tried all Vsync options, xrender, glx, and a lot of other options without any effect.

Using this fixes the problem compton --config /dev/null -f -D 50
But I need other effects too.