I have been having the same issue with some of my plants, so I been reading allot about it and only thing I can think of is over fertilization or possibly root deasease (pythium). Plants expell water from the roots if the medium is richer in fertilizer than what is in itself (trying to balance out the difference) this causes the plant to dehydrate and have symptoms pointing to overwatering and even heat stress (toco’ing like two of your leafs in pics). It is hard to really say 100% but I noticed it in other strains in my room when I upped nutrients, so backed them off. Waiting for results. Mine also was throwing 3 bladed leaves along with some deformed ones (tips pointing left or right) this could be the stress factor of losing allot of water and food, plants will release ceartain hormones in times of high stress to try and cope with environment.
Also watch temps and humidity at night, I read if humidity falls out it can coat the leaves with moisture and not allow the plant to respirate, plants breath at night, they take in oxygen and out co2 (opposite of day functions) to create more energy for photosynthesis, they need the leaves stomatas open, if they are coated in water they will not be able to exchange the gases they need too and will suffocate on there own gasses and will not be able to convert its glucose into energy for photosynthesis. This could lead to root rot, couple this with a fertilizer imbalance and you could have a sickly plant real quick because it’s night function (respiration) is energy stored for the uptake of water and nutrients.
Figured I would share my findings since I have been racking my brain about this too lol. Also no to the initial question, that is definitely not PM.
