What is it on top of the main cola?

Sorry to beat it! Let's get anal. Since it's not repeated, maybe a led is bad and focusing intensity like a magnifying glass starting a fire. Just saying it ain't the whole garden.

If it is in fact light wouldn't other plant tops be effected? And a larger rather than specific area? growdiaries.com/diaries/244831-chocolate-kush-bruce-banner-sativa-hybrid-grow-journal-by-novc01. (Week 20 5th to last photo). Just on top of one cola. It was it's own distinct yellow flower.

I agree with the others,bud bleaching from lights being to intense. Can fix that by dimming or raising the lights. Might be a good idea to get a PPFD number on what the plants are getting exposed to. Look at your lighting map and hang height from the manufacture of the light, then look at how long they are on for. can estimate a DLI from there. I like to aim between 35-40 DLI. closer to the lesser just because my tents environment is not always ideal and around 40 DLI is the max for ambient conditions according to some research done by dr.brucebugbee, Other wise its just wasited.

Too bad you didn't zoom in tighter when you took the photo. As I expanded the picture it looks like leaf not sacks. If leaf don't worry about it. If sacks, examine the whole plant for more sites. If none pinch it off and continue on. If more you have to decide chop it or risk seeding your grow. I had an albino flower on top my last. It grew normally didn't effect anything. Could be an environmental issue that caused it. Not gonna try and diagnose. Sack or leaf you decide.

A bit blurry, but yeah that's likely light damage... when pistils get singed they turn into yellow nubs. in real life i would think you can easily discern a nanner, if that is the case. the pictures are too far away and most are blurry.

Reminds more beginning of bud bleaching. Light too intense . My guess.