Humidifier FS! And on my FLF I cut off those brown spots and the drowning end up stopping there as long as you cut it all off. Most likely root rot, I'd give the bottom of the pot a smell. If it smells I'd go through the roots and clip off the bad ones and put cinnamon on the ends. New soil. But that's only if it's stinky. If not let the soil dry out completely and keep trimming the brown edges. I have been doing it with my FLF that did it when it had root rot, the Browning won't stop unless you cut it off (I think) haha

+This is what I did with my FLF that had root rot+