Ghosting in VGA signal generation
I believe there is sufficient synchronous noise crosstalk to the Hsync signal to cause jitter on the video which appears to get progressively worse after vertical sync.

A 0.1uF decoupling cap directly across Vdd:Vss on the IC is needed, not inductive jumpers to the breadboard rail.

All fast risetime signals with inductive jumpers are easy targets for mutual coupling.  I would add a  &lt;=220R load to attenuate crosstalk and/or use twisted pairs on each critical signal.



All scope traces need the ground clip to be removed with probe tip also and measured across a leaded resistor (tip &amp; Ring) Otherwise you see >20MHz false noise