Gorilla glue

That may not be burned from the sun. Is the 5 tsp per gallon correct? If so, dial back your nutrients to 50% of what the manufacturer states for their product. Flush before doing so to get rid of all excess nutrients in the soil.

Is this GG4?

We both my be correct in some way. If it's extreme heat we could dial the nutes back, protect her from the scorching sun with some shaded area that still receives light and see if she will recover. She is having to work extra hard now to compensate for the lost time since she is an Auto. Plus if her roots get too hot, she will run into root zone issues that may not be able to get fixed in enough time for harvest. I hope she recovers for ya!!