Leaves like as Leprechaun

Looks like issues with the root zone to me, could be from overwatering or lack of oxygen in the medium. as the new groth is ok but old growth is not. Your medium appears to be coir as well, its best to mix that with min 20%-30% perlite to assist in drainage to prevent lack of oxygenation from happening. If you coir has not been buffered before it will be robbing the plant of all its Mg and Ca and releasing a lot of extra Na and K as it has cation exchange sites that need filling. and depending on how your feeding them, your nutrients may not be enough. I;d suggest mixing in some CaMg supplement ASAP and maybe transplant into a pot mixed in with perlite and coir. Try and remove as much medium from aorund the root ball as you can. Good Luck!

Are you spraying them with anything??

Look up cannabis diseases and Viroids. I've seen plants with HLVd have misformed leaves like that.