Ok cool, since you're not using the trio they will want some N which they would get from Grow Big and Tiger Bloom. I would say feed with N fert and Big Bloom, feed every other watering with PH straight water, I like to give them cal mag with the straight water to offset the cal mag deficiencies with FFOF. When feeding with nutes I would go 1/2 strength then 3/4 then full. You can lay off the N and go mostly with bloom after week 4, but watch for N deficiencies. It is normal for them to lose foliage closer to harvest but she needs N too through flower to maintain healthy foliage. just not as much as veg. Basically since most of the nutrients are now depleted from the soil she's looking for N as well as the flower nutes you're using.
Its definitely not nute burn IMO.