Looks to be nutrient burn and calcium deficiency, Calcium is an important nutrient which helps provide structure to the cannabis plant and helps it withstand stress like from heat. When your plant has a calcium deficiency, the main symptom that you’ll be able to notice is brown or bronze splotches or spots on your leaves.
The yellow or brown leaf tips are caused by too-high levels of nutrients at the roots, which disrupts the flow of water through the plant and causes the symptom of burnt tips on leaves.
Your should flush your medium and check the run off to make sure that your not locking out any nutrients. Hope that helps you .