Hi guys!!
I know the pics are not so good hehe, it is not mold, maybe a fungus can make this, but...It is a burn!! I can clearly see the necrotic areas by looking the back side of leaves.
The humidity is around 30-40%, so im thinking is a nute problem
Im thinking about calcium, PH was around 6-6,5 until now, ill do an extra watering with calmag, adjusting ph to 7 just in case.