I have some that look like that, and its insect damage. I've been trying not to use the sevin, but I may have to do it.

Oh no! Not the pests. so No need to prune them I guess

Does not look like insect damage to me, and I wouldn't prune those leaves. Whatever it is looks minimal at this point. Have you fertilized it? or sprayed with anything recently?

Mine look worse than that and they're still pumping out cukes, I had to toss 50 of them in the compost pile the other day. We're done with pickling and the neighbors lock their door now when they see me walking around with a fat bag. Check for bugs but they look good to me.

party music I don’t spray it with anything I have used egg shells and banana water on these plants.

vgkg Thank you I will do

I agree that it looks to be minimal whatever it is, but still think some of it could be early insect damage. If you take a good look at the undersides of the leave and don't see any bugs then I wouldn't do anything unless it get worse. I would however use a mild fertilizer to boost its growth just in case it drops those damaged leaves.

Don't worry about it, seems like some sort of stress, really not much you can do about it at this point except keep watered.