Setup: 2 rows of 5 tomatoes each. 2 of the plants in each row is a San Marzano, which are a serious pain in the butt.

Two of the Marzanos, which are next to each other at the end of one row, are otherwise very healthy and rapidly growing, but have had yellow spots on the leaves for some time. There are no brown margins on the spots like with blight. You can see for yourself in the picture. What you see is the worst of it, but all the new growth has it. Otherwise, the leaves seem quite robust and healthy

None of the other plants seem to be affected, including the other 2 marzanos in the next row, or the zebra stripe right next to them.

I have been spraying with Serenade, which is OMRI listed and I have found very effective in the past with blight and such. I didn't see a change, so starting last week I even increased to concentration and sprayed every other day instead of every 5 days which was my schedule. Still, the new growth has yellow spots.

When I google image search "tomato disease" I don't see anything quite like this, as all the diseases with yellow spots usually have brown margins on the spots, and desolated leaves.

Any thoughts?