Last week? Maybe?!

26th March no

A week to finish plumping, then start scoping trichomes, maybe. If it is an evaporative humidifier, yeah it could have caused a 3-5F shift, but it won't be a large effect. This maximum effect depends on ambient RH% and volume evaporating per second, of course. The lower the RH the more an evaporative cooler impacts temperature, which is what a lot of humidifiers are - if it has a wick, it's the same exact thing as those evaporative coolers. As water evaporates, it absorbs heat. This is how sweat works... and why it doesn't work in 100% RH conditions. As far as the leaves.. have to feed it a more balanced diet... don't let it progress so far before attempting a diagnosis and fix. If you are "flushing" without a good reason, stop doing that, lol. If you have to you can crumble off the dead bits, but don't remove leaves unless the plant is about to shed it anyway. might as well let it suck it down, first. I'd wager potassium is on low side. if in soilless, crank K up to 180ppm, or if already there, that eliminates one reaction. Maybe something is locking it out...

There are multiple (long term) issues affecting this plant, but there is nothing you can do at this late stage to "fix" or alter anything. Just ride it out until harvest, it will be fine.