I’ve noticed mine is filling with dust on the reflector and inside the glass, i wonder if its not dust but is actually fine shavings form its internal spinning mechanism
I can’t seem to get a good picture these are the best i can do
I have not noticed anything on mine. I have one used when repairing cars and it has seen a great deal of use. But I will keed this in mind when next I use it.
Mine is, yes.
nope but i do have a problem with the tailcap 
the water is leaking from there 
mine did too, its not a waterproof (or water resistant) light
I took mine apart and dried its internals, i had a thread about it
I was thinking of taking mine apart and cleaning the reflector with distilled water next time i get some, hopefully that will clean it without damaging the reflector.
No dust in mine so far.
I’ve put a few hundred hours of use on mine, recharged the batteries maybe 50-100 times, so perhaps its something that occurs over heavy usage
Are you in a dusty environment when changing cells?
nope, though i did use the light in an dusty environment once (maybe twice), i washed it and water went in the tailcap
Don’t touch the reflector. Get a can of compressed air and blow it off.
I use compressed air on all my reflectors before reinstalling them. I blow out the inside of the head too.
I sometimes have to widen the hole by drilling it out and the entire reflector gets covered in powdered metal and filings. I don’t worry about that. Don’t wipe or blow on it with your breath. One shot of compressed air and it’s perfect and clean.
i don’t have any compressed air but it is a good idea, would distilled water harm it or should i wait till i can borrow a can?
You can get compressed air anywhere. Home Depot, Canadian tire, any store that has lots of electronics, computers etc. I got my last can from staples. It’s great to have around. Don’t use water, and don’t touch it. Get some air and blow out all your lights reflectors.
I like to use things i already have instead of getting more things when i can, but since i’ve read in other threads how easy it is to damage a reflector i will see if i can borrow a can
Personally, I think compressed air is more risky than distilled water. For sure don't use compressed air from a compressor. They collect moisture and dirt inside and in the lines. Usually have oils in them too.
I always rinse my reflectors with filtered tap water (really well filtered well water-no chlorine). I then carefully fling off as much water as posible with my hand cupped around the rim of the reflector. I then wrap it in a lint free cloth to finish drying (don't want dust to collect on it while drying). Many reflectors seem to have a very thin film of oil/dirt from the factory. So rinsing usually makes them shinier. YMMV. Beware, do this at your own risk. Reflectors are delicate, etc, etc, etc.
in that case i will try distilled water, the cans of compressed air are not actually air, they are a flammable gas, which i think is ironic, a can of “air” can burn, i’ve never tested to see how flammable though
The problem with the cans is that if you shake them or move them too much while spraying, they might squirt out some of the liquid and leave marks on the reflector
Is the dust filling light a warm white version?
My guess is that there is something wrong because of the emitter change, maybe a bit of thread lock would have been necessary…
it is neutral white (T6 3C) but it came like that from CNQG, i did not change it
In mine, the last GB, there was dust on arrival. I have not yet cleaned it.
My guess was that the reflector unscrews itself a bit from the pill, and because of that it rubs on every screwing inside the head…mine did that so heavily that it was sometimes hard to change the batteries because it wasn’t able to spin freely anymore. The dust got more from day to day.
I guessed that this was because after the LED exchange the thread lock was not renewed but maybe it always happens just more slowly.
Inside the head the anodization was rubbed away, cleaning was a disaster I needed a new head…