I think it may be possible that there is nothing “wrong” with your flashlight. Hope someone with better understanding of the electronics chimes in. I think it is likely that the problem is that your battery is not up to the task of powering the flashlight. This is the only flashlight I have that behaves this way and I think it is likely a feature not a bug.
The first thing I did with mine was to try a run test to see how far down it would draw the battery. On high, it ran out of regulation at about an hour and twenty minutes with a fresh EBL 1100 battery. Voltage down to 1.17 required 900 mAh charge. I know it is possible to run those batteries down to require over 1000 mAh and likely could have done so if I let it go at the out of regulation dim level.
At about an hour into the test I compared the E02 to my Ti3 on High. Very similar amount of light! This is truly incredible to me. IIRC, runtime on the Ti3 is around :40 and certainly no where near 1:20! How much of that is the difference between the XP-G and the SST-20 and how much is due to the efficiency of the driver? I am not sure but it is the most dramatic difference in similar lights of anything in my collection.
Have a couple of LADA 900s and an eneloop 800 AAA in addition to the EBLs. The LADAs and the eneloop work fine in the Ti3. However, they simply don’t fully work with the E02. The LADAs will come on low but as soon as I try high or turbo they immediately drop out of regulation and will not go above moonlight despite the fact that they have nearly full capacity available. They just can’t put out sufficient amperage to make the light work. On the Ti3 I can tell that it’s not quite as bright as it should be but it is kind of a subtle difference and the light appears to work more or less normally. Different kind of driver and very different results.
With good cells this light is amazing. With less than good cells it becomes about like a Solitare and can only put out something around a lumen. I believe this is tied to the incredible efficiency and the exceptional moonlight modes. Just not sure if that is correct or how to explain it.