The same here on my Atari 1200XL installation! 🥺
Very weird! In the past it worked right! Now it have the right colors but a very snowy screen!
I have try the sync from composite video either direct from cd4050, but with the same exact result!
I have right clear screen from the stock composite video, if I remove the VBXE and restore the removed components...
This is a PAL 1200XL using the GTIA PAL adapter form Dropcheck.