The things to consider here are this.
#1: Notice how on most of the plants that the new growth does not express your concerned issue? The plant grew out of it...
However!
#2: The real "suffering plant".....Has Russet mites! These do spread, kinda slow but, your plants are contacting each other...IT WILL spread to them in time...
I used to say that root aphids were the bitch to get rid of....Nope, Russets are...Hands down!
Get out the big guns! Pyrethrins, will NOT kill them all off!
FORBID 4F
AVID
Treat with the Forbid.
5 days later, the AVID
5 days later, Forbid
5 days later, AVID
Treat ALL the plants in the area! Including non cannabis plants!
Spray the soil around and under the plants with the Pyrethrin mix..
Russet mites are frick'in microscopic.....Your NOT going to "see" them, even with a little hand held scope!