I edited the above comment, there is something weird going on with their not being a differnce between 50% and 100%.
I got to thinking maybe the difference you are not seeing between 50% and 100% was due to the battery. My experience with Eneloop Pro is that can develop high internal resistance. This may be affecting your results. I also looked up your older reviews of the purple LanApple and the green Mini Pineapple and see you were getting a difference in current and output for the 50% and 100% levels.
I went and played around with 3 of my Reylights and different batteries and below are my results. I switched from a white eneloop circa 2020 to a out of the package circa 2023 and freshly charged Fujitsu 1900mAh NiMh. I don't have any fancy testing equipment, which is why I rely on reviews like yours, but here is what my eyeballs saw.
- Grey Aluminum LanApple 1xAA Nichia 519a: On the older 2020 eneloop I could not tell the difference between 50% and 100%, but when I switched to the Fujitsu NiMh I could see that the 100% was slightly brighter than the 50% mode.
- Purple Aluminum LanApple 1xAA Nichia 519a: Even using the Fujitsu I could detect almost no difference between 50% and 100% mode. The 100% mode may have been slightly brighter but it was subtle enough I wasn't sure.
- Green AAA Pineapple mini 1xAAA: I had thought there wasn't a visible difference between 50% & 100% in past usage, but I had been using older partially discharged Eneloops. When I switched to a freshly charge 2023 Fujitsu I could definately see the differnce between 50% & 100%.
Conclusion: I'm not sure. It could be the batteries or it could be the light, or some combination of the way they interact together on a battery that maybe can't handle such a high drain.