These pics show a pest problem?

[Dinger]

I got a few leaves that are showing this particular problem I used 60 times scope to look at the leaves and I didn't see any insects or anyting, thoughts and solutions?

Strain: Chemdawg (Seeds from friend)
Lighting: VIPARSPECTRA Reflector Series V300 300W
Pot: 5 Gallon Smart Pot
Medium: Mother Earth Coco 70% + Perlite 30%
Nutrients: Flora Series (Micro, Grow, Bloom)

Flipped to flower on 8/1.

Thanks in advance

 

[Itibitiguy]

Possible wind burn??? But you usually get a bit of brown around the edge of a wind burn

 

[Dinger]

Possible wind burn??? But you usually get a bit of brown around the edge of a wind burn

I just recently moved the fan from blowing down to blowing up and under. Maybe this will help

 

[Itibitiguy]

Sometimes a fan can rub a coule of fan leaves against something and cause wind burn

 

[Dinger]

Sometimes a fan can rub a coule of fan leaves against something and cause wind burn

Just hoping it isn't pests.