Calcium and magnesium deficiency......simple to fix, add a cal/mag supplement to your fertilizer line up!
Might be a bit late to affect a cure, but it should stop it from getting worse.
Pity you went so hard on the defoliation, those buds were relying on the leaves you removed to make the energy the buds need to grow to their biggest size.
Over fed too btw...........autos can usually get by just fine on half strength nutrients.
Remember too, in soil it is a schedule of plain water/plain water/feed/plain water/plain water/feed.........