Can anyone tell me what the problem is here

everything was healthy and green, then transplanted 12 days ago and flipped to flower 8 days ago. Now this is appearing. Thanks for any help and advice.

What did you transplant into? Used soil and what type? Possibly low potassium/phosphorous levels. Nutes used?

Mixed 1 bundle pro mix with one bag fox farm happy frog jump start. Using general hydro two part solution. Lots of foliage spray for mites recently . Still there was an occasional heat problem while I was figuring the Rom out. It's the older leaves with the spots and some. Of the very new growth is lime green colored. Plants are a little woody but they were very outbound from waiting to get the numbers down. I am new to gen hydro use just poop and organic liquids.

Looks like something was spilled on it? Maybe a spraying during high heat?