Well it's been "normal" for me, but I can't swear that I've experienced 100% healthy squash. Keep an eye out for any signs of other issues - such as mottled looking leaves that suggest mosaic virus, or a powder covering on the leaves indicating powdery mildew is setting in. Make sure watering is consistent, then don't worry about a couple of leaves if the rest of the vine looks healthy.

Susan

its basically going from the oldest leaf, to the next oldest leaf, in a line. Like I said, the end of the vine looks great and keeps growing. But these "older" leaves are dying one-by-one.

No sign of eggs, SVB, or anything like that.

I've never had a individual squash leaf last all season the older leaves die from the base out.