Lovely photography, and a very nice even floody beam profile.
I may yet be tempted by this unusual light.

As per the previous poster, I do think this is suspect. Perhaps your Panasonic and Keeppower have had protection circuitry added? The standard Panasonic NCR18650B 3400mAh certainly is not protected and not long. Mine are a hair shorter than 65mm, I don’t have a vernier with me for more precise measurement at the moment.