Looks like the defect has not manifested in the 4 in my Q8 yet. These poor guys got reflowed no less than 8 times. I have 6 more that I'm trying to figure out what to use them for. I'll report if any of them have the half dying issue. I have to say it again. I just love the tint and beam pattern with this emitter. The below pic is bottom of Ramp Mode.
Same here: several Luxeon V damaged the same way, but they got higher currents. The typical appearance as can be seen in Jerommels photos: about the third part (rectangle shaped) at one side of the die is darker.
Note: this is not always visible in low moonlight level! It can better be seen at higher currents through some filter (I use a writable DVD for this purpose).
Edit:
My LEDs were only mounted in reflector lights, so a force to the side of the LED is unlikely.
I will try the same picture tonight with the 4 lights on max. With some 10.500 lumen pointing at the ceiling I hope that no one will be disturbed 
The pictures I posted is taken on max output, I have build two quads and two reflector lights, I can’t see any irregularity’s in the die output in any of them.
I have been running them all hard and hot with FET drivers and VTC6’s and VTC5A’s.
Still trying to figure out if this is a random thing going on:
At what temperature do you reflow, Jerommel/Flashy Mike?
I haven’t reflowed them by myself, got them mounted on MCPCB, just like Jerommel (I guess).
That should be very ok, I trust led4powers reflows way better than my own.
I got them reflowed on 4040 boards too.
Very well done reflow indeed.
That’s the weird thing.
When you test them with very low current, it looks fine.
No mechanical damage on mine either.
The picture does show a small slightly blueish area, but that’s because of a sloppy, hastily put together aspheric test set up.
No, it’s just a sloppy set up, the lens was at a slight angle. Prism like tint shift effect.
Seem like the failures are most likely a manufacturing defect (as opposed to a design defect) as mine have been tortured with excessive handling and heat from reflows and high current. Took a pic in Turbo mode under welding googles:
EDIT: I just reread the above posts at the problematic emitters. I missed that one was working fine and then went bad. Seems unlikely to be a manufacturing defect when that is considered. Djozz's hypothesis makes a lot of sense. Would be informative to see how evenly the failed emitters lighted up with the domes completely removed.
If I remember right maximum current decreased also when the LED got damaged. Don’t have a flawless LED currently for comparison.
^
When you look at that emitter from the sides that the thermal pads extend out to, do you see indication that there is adequate solder between the emitter's thermal pad and the base?
EDIT: That may not work. The thermal pads don't extend all the way to the edge. Probably the best that could be done is to unreflow the emitter and see if it appears there is an adequate amount of solder on the thermal pad.
Checked 2 boards, there was no excessive solder on the visible ends of the center pad. So I unsoldered the LEDs and there is solder on the center pads of LED and board.
^
Thanks for checking. We expected that based on who reflowed the emitter, but it would have explained the drop in current and damage to your emitter if you had found otherwise.
If you don't think you will ever use that emitter in its current state, you could try a hot dedome. I would do it by reflowing it back onto a base. Before it cools (but after solder locks up), lift off the dome with a pick. The dome might break up. If it does, just try to lift of as many pieces as you can while trying to not remove phosphor. If you do remove phosphor, that is ok, but you will be left with a UV or Royal Blue emitter. After the emitter cools and you hook it up, put on some UV/Blue eye protection (if you lost phosphor) and power the emitter up. If the light is now evenly spread across the die, djozz's theory is correct (i.e. There was some separation of the dome from the phosphor) and you now have a dedomed Luxeon V.
Because?
What if the chip wasn’t properly soldered to its 4040 base?
You can hypothesise all you wish, but the LEDs were not mechanically abused, only saw 3 Amperes max.
The blueishness is only there in the picture because i had the little aspheric a bit askew.
You can see on the opposite side the yellow sticks out.
(I thought i explained that already…)
@ImA4Wheelr:
I might try that when I find the time but that wouldn’t explain the lower maximum current after the damage, I guess. I don’t know how this LED is build but I rather suspect some broken electrical connection in the LED. My damaged LEDs look exactly like the one shown by Jerommel, and with a separated dome I would expect some variation.
‘Expert’ is very relative here, everyone here is a good meaning amateur, just as you are. No one is claiming to know what really happened, and every one hopes that we will find out together how it can go wrong because this is one of the more interesting leds at the moment.
Edit: you re-phrased your post 
I'm detecting a bit of frustration/anger Jerommel. If I sounded like I was trying to say you're to blame for the damage to your emitters, I apologize. I'm not. I just really, really like this emitter and want to know what is causing these failures. I wasn't counting the reflow as part of the manufacturing process of the emitter. I completely agree that if the base's thermal pad is not adequately connected to the LED's thermal pad, bad things will result.
If I come across as trying to sound like I know what I'm doing, I again apologize. I think I tend to write in a way that makes me come across as sounding authoritative. I'll try to watch out for that more.
I already deleted “experts”, it sounded too offended.
Both LEDs look like new, mechanical damage like you proposed would be visible to the naked eye.
Yes.
My first reaction when i noticed a problem was: Jerommel, what did you do wrong this time…
Then i doubted the reflow on the 4040 PCB, so i desoldered it, only to find out it was reflowed perfectly by Neven.
I had a somewhat similar thing with the XP-G3 in the Manker E02, only that one was half lit on low current and fully lit on high current (by the way, i replaced that one with a 219C).
I’m over it already, don’t worry.
Yeah, i was a little annoyed…
I would never claim something to be a faulty product if i wasn’t certain i didn’t damage it myself in any way.
I can understand you don’t want this product to have problems.
Neither do i.
