Some of the fan leaves are getting these spots and look a bit lathered. Anyone know what the problem is? Today is day 41 of veg. I noticed it last week on a couple fan leaves now it's starting to get worse.
This is mostly pest infestation. Try a soap foilar spray. I would usually pick my maginifier to check. Once you do so, you will see these little white things are either small or larger aphids.
I have had good results on my outdoor grows using Safer 3-1 spray (insecticidal soap plus sulphur). I use it every 7 days as a preventative in veg and as needed in bloom up to a few days before harvest. HTH, YMMV, IMHO, etc.