What caused this??????

So I live in Colorado and its officially winter time gets cold and my temps when lights are on are about 80 and in the night it gets quite cold now and too.boot my gas got shut off so no heater till I pay it I know this ain't no nute burn because the brown area is not crispy its super soft weird this is the first ploblem I encountered today is it frost bit I put them in the downstairs closet at night?

Was there frost on your actual leaves?

Didn't give much info about the lights, etc, but that looks like a leaf got too close to a CFL.

No cfl just a t5 and 1000 w cuz she's in flower and.light is 4ft to 5 above my girls and no frost was on the leaf at all.