Well you have enough light... temps and RH is acceptable.. only thing to look at now is your nutes.... what are you feeding them, and how often? do you ph before feeding?
Glad to here you new plant is doing well, but damn... that other one looks pretty bad.. Who knows what is causing it.. but if I were you I wouldn't take any chances...
Transplant in new soil... flush... wait 3 days flush... then start her on nutes.
Here are my babies 9 days into flowering !
My third sick plant turned out to be a boy, so we smoked him lol.
I'm using the first two foxfarm nutes and will be getting the third one soon.
H around 40-50
Temps get upwards to 94 if I dont leave one of the door cracked open.
Temp with the door cracked, about 80- 85
Carbon filter up top keeps all the smell down even with
the door cracked.