Well I'm not ruling it out, although mites could certainly be an issue. Plus once you breach the leaf's protective waxy cuticle, disease can attack much more easily.
You may very well be having dewfall at 'night'.
Are you running your day/night on the opposite cycle as the REAL day./night? That can help control your temps and avoid dew.
Either mold or mites, neem is a great tool - it leaves a waxy residue and really protects the leaves- and you only have a few more days to use it before the buds start putting on mass, after which time you can add an unpleasant aroma to your product.