Acct #2 Powder

I noticed my Accurate #2 powder turning dark in my reservoir. The powder  drop is a redding  #3. The canister sits close to a small Florence light. also I keep my reloading room cold (its also my bedroom). any ideas why   the powder is turning blacker.

This powder does not burn when I fire it in my pistol.

Moisture, maybe.

UV light is a killer.

Your're not supposed to leave powder in the hopper overnight.

There's a reason every powder container is opaque.

THE powder does not burn? That is serious contamination. Chemical breakdown, even from UV, should cause it to turn rust colored and start emitting nitric acid vapors.
I would contact Accurate and talk to them.
I do wish all powders still were still black from being graphitized.