Video issues/Noise

[Xukkorz]

Probably known but some games will exibit noise occasionally. Sonic 1/2 both seem to have the issue. It almost feels like either video is out of sync on a de-interlace or something like that. Does not happen every time, I've noticed some time going from an old game to Sonic forces it but not every time. I have had it working fine in Sonic 2 then post special stage it causes it to look noisy. Almost has combing like artifacts but clearly not a full interlacing problem.