Sorry, Fuzzy, about your late-stage rough patch here - that sucks..
I guess opinions are like assholes.. but, what I see there is a plant that was supporting a lot of foliage and budding activity up top, then along comes a flush that probably stripped too many nutrients out of the soil. I've seen with my own plants how, by the end of stretch, they've pretty much exhausted that soil down to a mere medium, and are reliant on the grower to keep adding what it needs from there.
What's probably happening with the weight is that the buds are releasing water back to the soil in order to get the concentration of nutes in the plant back to where it should be, using it's own stores (since the soil is exhausted). That would explain why she's not transpiring any water anymore, too.
Good news is.. you're probably not losing any smokable material, and MJ really protects its buds at all costs. So, she should pull through anyway.
I've come to not like flushing all that much. I flushed my way out of an over-nute situation last year. It corrected the over-nute, but then introduced a bunch of other weirdness. The whole business about flushing to remove nutes, improve taste blah blah has no basis in plant science.
I don't know what more you can do other than what you're doing. It's tough to course-correct late in a grow when the plant is not creating new material.