Leaves deficiencies flower

This looks more like potassium is wanted, possibly calcium as well. The plant shows deficiency in a few days if it is not getting enough. Flowering npk ratio is 1-2-3. Nitrogen levels were too high prior. When it's too low. Lower leaves will turn yellow and the yellow will work its way up depending on how bad it is. You should never cut the nitrogen completely since there is other nutrients in that feed. Just reduce it greatly

Could also be too much light as well. Have you checked the temp at your canopy and then have you checked your PAR or PPFD as well?

Yes, way too much nitrogen, which is the cause of the burned yellow/brown blotches. Remember...........what is showing in the leaves now, is a direct reflection of what was occurring in the root zone 2-3 weeks ago. So, even though you have reduced the nitrogen levels, there is a time delay before the leaves will show any difference. One feed and a couple of days will not solve anything. Remember too, in soil it should be a schedule of plain water/plain water/feed.......plain water/plain water/feed. Getting a decent amount of run off each time you irrigate is also vital. Calcium deficiency will show up as leaves with brown circular dots, not random shaped brown blotches.