Thanks a lot for posting your observations, g_damian. I will let Wurkkos know about this UI issue, so they become aware of it. Hopefully, this will be rectified in revison 3.0 of FC11 (with type C-C cable support). I also noticed rough edges on cooling fins and tailcap chamfers on my prototype sample and suggested Sofirn (manufacturer) to improve the manufacturing process. However, it seems there's little margin left to do some extra post-treatment to those things as FC11's price needs to be kept very low. The same will probably apply to the missing anti-reflection coating on the glass lens.
I want to add that the UI is changed now. There is hold from off for moonlight, and no more long press to turn off. The bug g_damian mentioned exists but seems like it doesn’t effect normal use too much.
I swapped a 3500k LH351D into mine, I’d suggest those who like warmer LEDs try it. The stock 5000k LH351D had enough green tint to bother me, I have some of the “dogfart” LH351Ds that seem less green.
I actually added 1/8 minus-green to mine and it feels perfect…at the expense of some throw, of course.
Rough/sharp edges exist on all my Sofirn lights and I personally find it taints the experience. I know we’re talking budget lights, this is BLF after all, but I’d rather pay a little extra for nice chamfered edges.
Thank you for your feedback, i will test the bug of ui and feedback to the engineer to fix it
Better slice it 
I think I may just outright replace it. Even the CRI seems a few points less. I think they changed what they feed the dog
I sliced it after all:
Don’t know if (known) bug or error with instruction manual.
In both modes, continuing to hold button from OFF does not do the intended action and instead switches between modes.
Excerpt from manual below.
Stepped mode:
From OFF, hold 1 second to Eco, then keep holding to cycle through stepped modes.
Ramping mode:
From OFF, hold 1 second to Eco, then keep holding will adjust brightness steplessly.
You could try with the front lens off in case an AR coating is affecting it.
It’s a plain lens, no change.
thanks for posting your data captures (I summarized to show change in duv and R9):
still smells like a dogfart
From what I’ve found, the bug is only when the flashlight is in stepped mode. I don’t have this problem when in ramping.
Received the FC11 today. Battery is charging, so I am currently using a Samsung 35E protected button top to test out the light. Liking it a lot so far. The magnetic tail cap is pretty strong…
Here it is stuck to the Real Steel Flying Shark. I even moved the blade around a bit, but the FC11 held on.
So how’s the pwm for this light?
@Swabs:
Nice Firesticks!
(the succulent in your yard.)
Tendou - I don’t notice any PWM. I think the light is really good.
raccoon city - Thank you.
Thank you. I will get one then
This flashlight is pretty amazing for the price. I am very happy with it. But is there any special handling of the battery necessary?
This has been my EDC since I received it. It has a great (for me) UI, and a nice beam. Its easy to carry… it has never accidentally turned on in my pocket. The light is usable… good temp, no tint, high CRI. It has C-C charging that works. Its a really nice flashlight. My only wish is that the side switch was lit when the light is turned off.