Here is link to your previous post of this same question. Lots of replies there.

https://www.houzz.com/discussions/yellow-squash-leaves-dsvw-vd~5322911?n=12

Dave

Rather than wade through the other post, here's what I suspect.

Several years ago, I saw this at several different gardens in the Portland, OR, area. Plants were fine as far as water and fertilizer go.

Virus was suspect but didn't prove out.

"Affected" plants did well though the season, including production.

So, the cause is still a mystery.

Leaves got worse and changed?

I mentioned the possibility of Downey Mildew to you last time. Did you do any treatments? Any fungicides? If not, then yeah it gets worse fast.

Now the crinkled edges mottled mosaic pattern in the leaves, even new growth usually = CMV which is viral. The definitive clue between them is malformed, warty fruit = CMV

http://clemsonhgic.wpengine.com/wp-content/uploads/2018/03/cucumber-mosaic-virus-cmv-on-squash-.jpeg

The rest of the plant looks healthy in the pics so get rid of the affected leaves at least.

Dave