It would be a lot more productive for everyone if we tried to figure out just what deficiency causes the odd rusty splotches.
We've seen the burned edges and curling and fade before. I used to get that on a lot of my plants but I had hard water to start with, and I've just let mag deficiency ride. It's also not unusual for issues to show up around the time we do the Cat drenches. I always associated it with the drench, but it might also be something that shows up a few weeks into bloom, about the time the plants finish setting their buds.
I know from my own experience that the yellow crispy leaves can come from several things - too much light, too much spraying, salty soil, cold soil, etc. Also, Cat needs a supply of cationic minerals to work right. If the soil hasn't adsorbed enough, there won't be much to release, and you'll get abrupt starvation. The charge in the soil changes and the previous minerals aren't available.
This would actually be a good time to get out the rake and check some stuff.
Just to know, right? Some pH readings would be nice, for instance. These are deficiencies after all. I'd also be talking to people like Bobrown and CareStaker, who are living-soil freelancers and actually can diagnose stuff like this. Find that photo series that has all the deficiencies, etc.
It's a compound thing, I think. Something is getting in the way of another thing. The issue with the crispiness has been around for awhile. The blotches are severe and come from an internal problem, not foliars, etc. The delivery system has to be pretty screwed up to cause that pattern.