Day 49 of flower

You definitely want N for a good part of flower, especially stretch and bulk. If you notice the plant bounce back/take off when cutting N you may be giving it to much, dial it back from what your using now, next time. Depending on what cut it is I cut N the last 10-21 days of cycle. When I say cut I mean completely remove. If your "cut" is just a large reduction but still have some N you can cut it back earlier but the timing/amount is very cultivar dependant. It's a dance of finding the right time to cut without it impacting yield. My default when growing a new cut is the final 2 weeks. Then depending on how the plant responds to that, the next grow of that cut I will cut earlier/later. Defoliation will also cut the amount of N available to the plant if you wanna cut for N tox or finishing, but that's also a dance and cultivar dependent. Some have no problem with it and other strains struggle and you'll take a hit to your yield. If your getting lockout of other nutrients from N it's from too much, not from cutting it too late. So next time dial back the N on the next run at the appropriate times, could also be from your irrigation practices, you may have the "right" amount in the solution but may be getting build up, but that's easy enough to see by overall EC rise.