Do I have a foliage disease

[Utes1972]

Hello all,
I've got a mixture of heirloom and hybrid plants growing both in ground and in earthboxes in Salt Lake City, UT. We're in the middle of a 2 week 100+ temperature streak. Humidity is very low, no rain, no overhead watering, but my tomatoes are kept well-watered with a drip system. Today I noticed on just one of my plants, an otherwise very healthy and robust 'Mexico Midget' (growing in an earthbox) the following foliage defects shown in these two images. None of my other plants have anything like this. I thought I'd poll the experts to see if I have something and if so, what I need to do about it.

Thank you for your time.