Well dude. I just had my first grow and it had PM. It was VERY easy to tell apart the PM from the trichomes. I mean especially since it hit way before flower. HOWEVER. I've had two very tiny outbreaks of powdery mildew during the end of this flower. And i have trichomes extending far out into the sugar leaf, when the PM hit, it was literally a circular blotch of white shit. It was instantly recognizable that it was not trichomes because its almost like if you took that area of trichomes, multiplied it by two, and then stacked all those trichomes back together so its like a realllly thick dense of trichomes. It just doesnt happen though.
I always clip any leaf that has those blotches. I honestly cannot tell if yours is PM or trichs. Did it suddenly develop trichs or was it just an outbreak of PM right? Just try smudging it with your finger.. Pm is sort of hairy and it compresses and looks weird when you squishes. Trichs arent affected as much by some finger play. Your buds look hella weird compared to mine though.. I have like a nice even and consistent distribution of trichs.
Here are two pics of my nugs, and these pics dont do em justice ,but they are verrrry nicely frosted. The trichs extend pretty far out, and if there was PM on it, you would legit see a WHITE ass spot.
Honestly dont know if yours is PM or trichs.. but it sort of looks more like PM to be honest, especially with how it just suddenly ends towards the end of the leaf.