I would usually follow Rusty's advice if he dropped in on me, and I'm not being contradictory here. Did your bloom enhancer contain a significant amount of N? I only ask because I have had N overdose in flowering on a couple plants and that is exactly what they did. All the leaves near the tops bent down and curled under.

It makes sense to me since N is a mobile nute it can effect the tops without getting to the older growth.

Using that MG soil, you may need to flush a little more often, and be careful using any additives. MG doesn't really play too well with others (it's like plant crack) and the nutes it contains are usually designed to last up to 3 months.

Just thought another perspective would be applicable here.