I’ve found Ivy at least tries to make things right, if the order is taking too long or they make a mistake.
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I wrote to this email adress. Hopefully they are willing to help.
It’s unfortunate that this is still a problem. In my case it is only about 15 $ (iin worst case, if I don’t get an answer, I don’t care about this), but what if a expensive flashlight is lost during shipment…
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I have measured a 519A-V1, but the differences to first gen 519A are really small and I also have this LED in the chart shown in the 519A test. I don’t think I will make a dedicated test for this since I would have to simply copy-paste text from 519A (V0) test… 
Ive been seeing greener 519a from Convoy
[quote=“koef3, post:1, topic:223258”]
It is very likely that there are also “green” variants of the 519A with a duv well above 0;
[/quote]
true in my experience… the LED in the pic had a positive DUV of 0.0052 
before dedoming. That is why I wanted some Pink FFL351a 3750k, but, Ive been losing at the lottery…
Thanks for sharing Jon. I’m shocked and disappointed that the new batch is not rosy like the previous one. I got lucky and probably bought the very last of the rosy batch. I’m not sure if FF made it more neutral due to many people complaining about theFFL3451A on reddit they don’t like super rosy and prefer neutral or whether it is random batch to batch variation. If it’s random batch to batch variation like the CREEs, then there’s no longer a reason to be excited about this emitter. We will need to wait for more data to come out to see. But in the meantime, we should email feedback to FF letting them know we prefer rosy over neutral.
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That’s happened to me before too but don’t worry, just let FF know. Sometimes he takes a long while to check his messages and respond but Jack will always right a wrong. He’s a good guy.
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Has he another email as the Ivy-one mentioned earlier? I wrote to Ivy-email some hours ago.
This is their email. Not sure if this is the same as the one you sent to. FF-light@hotmail.com
Jack is a good guy but I bought 4 lights total recently, and 3 were very neutral. I reached out to Jackson for some ‘rosy’ ones.
Disappointing.
let us know how that works out
Jackson posted he has almost used up his last order and has a new batch coming… (that may be like the 3 you got from Jack)
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I wrote to Ivy and got answer today.
He/She apologized for the delay and sent a new package immediately. I also got the tracking no. already. 
Perfect service, I must say!
They put also a nice little gift inside (5pcs FFL351A 1800K) - how funny, as they could read my thoughts since I wanted to test these emitters
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I’m glad they made it right. Hopefully it arrives quickly, instead of taking 2 months.
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Yea I remember when Jack had Enogear before starting Fireflies, he gave me a nice free flashlight too when he messed up my order. That’s one reason why I like this brand so much other than the fact that they are innovating and pushing the envelope more than other flashlight brands.
Also I got an answer from Jack. He said he intended to make the latest batch neutral on the BBL duv by using less red pigment so it is by design and wasn’t a random batch to batch inconsistency like the Crees. That gives me hope. I tried to tell him most people prefer rosy negative duv like the original batch. But he might be thinking on the BBL is better for photography light since the FFL351A will be used in the NOV-MU2 photography mule. Guys you should email him feedback on what you prefer.
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thanks for sharing info
here is a report of an FFL351a 5000K w an Opple 4 DUV of -0.0014
https://www.reddit.com/r/Hanklights/comments/1coxm52/d4k_quad_ffl351a_5000k_opple/
the same person (jlhawaii808, who offers D3AA w FFL LEDs) has previously posted much lower DUV on his batch of FFL351a 3750K
so, there definitely are different DUV FFL351a circulating
disclaim
I realize the report Im linking is not for 3750K
also aware that Opple 4 is not a science grade meter…
For me, (almost) every LED has it’s own advantages and it’s place in the big world of lighting devices. For me, I am very excited about these 1800 K FFL351A, these could be very unique and very special with some sort of ultra-warm white throw. The HL2X 1800 K is just floody due to the dome.
For photography an emitter on or slightly above duv (for colder CCTs) is much better as red-boosted rosy tints. This is also something I saw in my measurements, more red, more saturation, which could have negative effects on photos.
The tracking via YunExpress is legit, it tracked properly, so it’s no fake tracking no.
Now I am waiting for the order to finally arrive. On a sidenote, interesting that I never got any shipping information or notice back then, just like the order was completely forgotten. In the order overview (with the map embedded in) there was also no tracking number, it was just blank. Now there is also the tracking no via YunExpress shown.
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Here is something that I determined as part of a quality control measure and creation of an algorithm for creating a new process to measure luminance.
This diagram shows the ratio of the FFL351A 3700 K 95 CRI tested here between luminous flux and brightness in a reflector at a defined operating current, from 0 to 7 A. The x-axis shows the current, the y-axis the ratio between luminous flux in lumens and brightness in lx. The labels are in German, but certainly still recognizable.
The red line is the trend for these values to get a smoothed dataset for easier comparison.
The brightness was measured in one meter, the LED sat on the large heat sink with the fan switched on, as usual from the tests.
The luxmeter can exhibit a slight non-linearity, whereby this curve looks different depending on the LED type (especially domed/domeless and the design of the LED chip). This effect also occurs with my other luxmeter, to a similar extent. It does indeed seem to be the case that the brightness does not increase one hundred percent linearly with the luminous flux, but is subject to fluctuations.
I don’t know exactly where this effect comes from. It is possible that the refractive index of the silicone changes with increasing current and thus increasing LED chip temperature Tj. The phosphor could also promote altered radiation behavior. In any case, this effect - as far as my data already allows - is less pronounced with LEDs without domes.
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Very interesting discovery, I always assumed lux/lm is constant across current levels but that doesn’t seem to be the case.
So even for the same flashlight, it might not be accurate to estimate relative output of different brightness levels using a luxmeter.
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This is true, but we are talking of only some percent of difference in luminance (and brightness). For me as LED tester it might be somewhat relevant but for flashlight enthusiasts who want to measure the brightness it should not really matter.
To get more reliable data I have to measure this with another lux meter and more LEDs. Since I am completely busy with updating all my tests to the most recent testing standards in the moment such a research is not really possible unfortunately…
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This so strange! The effect is not just not monotone, but also flips in convexity with higher drive currents.
If the effect is less pronounced with domeless LEDs it would seem reasonable to conclude that the effect comes from the dome, though it’s quite unclear to me the exact mechanism as the relationship is not monotone. I would be okay ignoring this effect in practice as the maximum variation is less than 2%, well below performance variations between LEDs of the same type.
I see that Fireflylite has added a rosy 4000K option, although the CRI is less: FFL351A 3V 10W 3535 Emitter
