Suspecting Nitrogen Toxicity

B-52 is worth trying, but keep in mind it has 2-1-4 NPK. Also, get TDS or EC meter asap. You need to make a test solution with the same concentration of nutrients you give her and check ppm. Should be 800 max since your plant is small. Without LST it would be 30 cm max I guess. I would say you need to give less nitrogen. Just little less. Switching to flowering fertiliser with lower N will help. I could calculate your ppm without TDS meter if you want, just pm me. But we don’t know how much nutes stay in soil. Another thought: I don’t know if you ever watered till runoff either. That’s important to allow some salts to wash away. And finally, what’s your watering schedule? It’s hard to overwater if you give only 500 ml per day at this stage. Fabric pot also helps soil to dry out very quickly. It’s better to water thoroughly till runoff but not frequently. I used to water 4L at least till I get 20% runoff, and wait about 3-4 days until the pot becomes light. When soil dries out, the nutes stay in. And she has to take in all that stuff with the next watering if you feed continuously. This way concentration of nutes in soil raises up and your plant eat too much. So runoff when watering is really good thing. Flushing, TDS meter and proper NPK diet could help here. But first, please let me know your watering schedule and do you feed continuously or every other watering?