Hi Mr caledon

Looks like a generally healthy plant that is starting its fruiting phase and coping with a combination of issues: Dry/soaked uneven watering, nutrient transport to developing tomatoes and perhaps not hardened as well as you could have. But nothing we haven't all seen and in my case quite often. If you have iron and epsom salt hit it lightly with them, if not, increase the fertilization around 20% if you are controlling that and be sure to water more evenly from now on ... and as usual, not to over-water.
my 2c
PC

Agree. If this is only on the older bottom leaves then it was a water/nutrient transport issue early on. Is the new growth all healthy looking? If symptoms continue to develop then you have a nutrient/watering problem that needs to be resolved. Vacations, during gardening season, love to come back and bite us. :)

Dave

Thanks for the info guys! Relieved to hear it. I'll give the upper growth a close look tonight but I'm pretty sure it was fine. I'm thinking uneven watering is the main culprit. I think I started them a little too heavy on the water and then gradually scaled back in recent weeks.

Since this foliage obviously looks unhappy, is there any benefit to pruning it, or just leave well enough alone?

I would leave the remaining ones on until I was sure, and would have removed the first or two if they touched the ground like you did. The plant will take care of the rest on its own. At the first sign of anything besides a gradual loss of color and drying out from the centers of those areas, then I'd do something. But if that is all, my policy is to keep them on and let the plant naturally shed them when nothing much else is happening.
PC