I would remove effected leaves and not worry for now. We have had a lot of rain, and it could be damage from sun hitting water on the leaves or mechanical damage. I find that most plants in the tomato family outgrow leaf issues. I haven't had anything spread from tomatoes to eggplant.

One thought is to go out at night with a flashlight to see if there are invertebrates chewing on the leaves.

I found tortiose beetles on my tomato plants and Japanese beetle larvae in the ground but nothing in or around the tomatillo plants. The yellow sports are actually raised bumps. I am taking measure to control the pests in the tomato beds. I can apply them here as well. The yellow raised bumps are just new to me and I was concerned it was a type of fungus. My dad has had a garden for over 20 years and said he has never seen this before.

Best to foster health in your garden and allow natural predators to manage insect pests. I like knowing that the produce from my garden is pesticide-free.

You could ask on the veggie gardening forum to see if anyone else has ideas. If you haven't IDed pests it is difficult to control for them effectively.