Faulty driver. Pictures not that great, camera lens was 1/2 inch from driver, used x6 for light. Probably should have turned the driver to get the other side of driver out of shadows.
Different angle.
Welcome skipper, you might need to start a separate thread in the wtb sub forum to find help there.
I’d resolder the OTC, those solder joints don’t look that great. It’s the darker and smaller of the two caps, if you don’t know what to look for.
Here you go, it was not easy to get the illumination right: the leds glow the same way so I guess this is not the cause, the different intensities in the picture are caused by the UV-illumination.
The best way to find out if it is the led or the light is of course swapping the leds between the two lights, but I'm not prepared yet to do that.
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@saypat: I know what you mean because I also lack a few aspects of the modding trade, and people who do know how to do it make it sound too easy. My weak point: although I'm pretty experienced in several sides of modding flashlights, driver design electronics and computer stuff like downloading, tweeking and flashing driver software is out of reach, I do not have the skills, the right computer (ancient Mac) and the will to develop all this (probably I love to dive into this after my retirement in 17 years time 
). At the same time I love to use all the FET-stuff that is thought out at BLF to make better brighter flashlights, the pro's make it sound easy, just change this and that resistor, double the cap, adjust the voltage divider settings in the software, add a gate resistor (gate resistor???) all those things I'm not good at. I bought some Attinies from Richard with the BLF-A6 software, but the first driver I have build with it (the 15mm FET+7135) acted weird, for each trace lay-out things perhaps need tweaking, or I might have used a wrong or wrong quality cap, I don't know.
So I'm glad for my sort of people that there is the off the shelve BLF-A6 driver now, and I happily use the FET-modded AK-47 drivers that do not have the perfect UI, but work pretty well for most of my mods.
That said, I think that whoever buys these BLF designed group buy lights should accept some trouble with them. Even though the design process has been fairly extensive, the fact that there's a cooperation with chinese manufacturers involved with all the difficulties that come with it, and that the design team are still amateurs trying out fairly daring things that have not been done before (wonderful things, and the team is getting more knowledgable every day but still), makes the chance of a less than perfectly functioning light very real. That is compensated by the good price payed. So I think it is fair to expect a limited amount of DIY from the buyers to get things working if needed.
Thanks Chouster but that is beyond my skills, will be lucky if I can solder another driver to the led board. Not much of a modder, too small for me and my decent soldering gun died after one use.
Not replying to, I’m simply reposting this brilliant piece of trouble-shooting. In trying to keep up with the new posts, I noticed this could possibly be the solution for those having difficulty getting out of an unwanted mode that tenaciously keeps returning: Have you attempted to toggle mode memory off, and then set the desired mode? Do that before assuming the driver is defective.
This is where I ended up, the driver is all over the place, switches between these modes randomly each time I turn it off. Driver was removed from light to take pictures. Yes, I did try to turn mode memory off, no better.
Oddly enough, both of mine are now working fine.
lol.
you cant make this stuff up - I tried countless times to program both of my lights to have mode memory… both would program successfully, and then revert to factory default when changing batteries or when unscrewing the tail cap…. now they both have memory from when I programmed yesterday even after changing cells. 
jmpaul320 maybe it was the old saying got ya…… “you just wasn’t holding your mouth right”
Just joking, it IS an odd thing, but I am glad to hear the lights are working right for you now and hope they stay that way.
it was probably user error LOL.
That looks like the driver is actually missing a piece.
Note the part labelled “471” stacked on a capacitor here… that part is the bleeder resistor required to make the modes function while a lighted tailcap is installed:
Your driver doesn’t appear to have one:
The 471 is there on Southlands driver, it is in the shadow of the red wire, going from led+ pad to ground, it has its own pads now
FWIW, config mode isn’t memorizable. It doesn’t even have a mode number.
The modes which can be memorized are the regular non-blinky modes, strobe, battcheck, and biking.
In theory, the mode group selection mode and thermal calibration mode could also be memorized, but the first thing they do is go back to mode zero and save, so they prevent themselves from running more than once in a row.
I know it was said earlier, but for those lights that don't seem to power reset unless you take the cap off (southland's), it seems related to the bleed resistor and/or tailcap LED, or some sort of short goin on. I though it was said way early that the lights were going to include a spare standard switch to eliminate the lit tailcap, but that didn't happen I guess. They have a spare solid rubber cap, but that of course doesn't eliminate power to the tail LED.
From the pics, all looks ok but it's hard for me to get a good look at the solder joints. Maybe it was stated, but wonder if you take the tailcap off and try to operate the light in modes/config with a wire or metal contact from the battery end to the body, if the light seems to work 100% normal then. If so, then pretty much isolated the problem to the tail.
I found in my Cu X5, I took the tailcap apart and when re-assembled, the switch is jammed up against the rubber cap and is extremely sensitive when ON. I either need to loosen up the retaining ring, or trim down the tip of the button. Could be the plastic ring is giving or bending under pressure. Not sure, but maybe something like this is contributing to the problem.
I think it's the fresh boots making them touchy. You can cut the middle pin on the bottom of the boot down a fuzz to make it less touchy. I prefer it to be touchy like it is honestly. It helps when you are working with gloves on. I haven't carried these lights much but I haven't "accidentally" bumped it or anything yet... I'm right on the verge of snagging some aluminum versions just for the x5.
0.72mA huh? That seems like a lot to be constantly draining from a 650mAh cell. I tried orange LED’s and it took an 0.81mA drain to even get a soft glow, ixnayed those.
I’ve made some changes and have mine down to 0.14mA, with a hot pink and a blue LED showing a soft glow not visible in a lighted room. It was that or kill it off completely.
It’ll be interesting though to see what some of those are measuring that are having trouble, wonder if it’s really in the tail cap lighting or due to something else? I’ve been seeing that the long delay in reversing is due to the lighted tail cap resistance… removing it has made a difference in an Al X5 for sure. I even built an entirely new driver with the A6 firmware on it, still wouldn’t reverse without a 5 second delay, pulling the lighted tail cap made it work pretty much as normal with quick half presses for the reversing action. So it’s in how all the components are playing together that is causing the differences in off-time delays apparently. Now what can we do to fix that? Quite probably something ToyKeeper alluded to, the driver and tail cap need to be redesigned together, as a unit. Makes sense to me…
So far on two lights I've upgraded to TK's latest Bistro (Jan 16), both lights (SS/Cu X6, Cu X5) now are timed much better (shorter) on the OTC for reversing modes. I did increase the resistors in the tailcap though on both of these, so can't see it was the firmware upgrade or resistor change.
The X5 looks great with 13K resistors and two yellow LED's - doesn't throw any light to speak of but very easy to see in the dark.
How did you flash firmware? What did you use? Do you have a link to a guide on how you did that?
I like the one blue tailcap light as is. I did the spring bypass tail and head both using short 18awg. The short tap is very responsive and so is the reverse. It is a very noticeable difference. I didn’t want to but now I’ll do the same to the ss/cu and check results.
Edit: I bypassed the X6 ss/cu as above and the response times greatly improved. Very light touch forward and much faster reverse. Hey…it’s better for me!