Troubleshooting a curious issue with my EagleTac MX30L3 - potential electronics help

Hey all! I have an EagleTac (Eagtac?) MX30L3. Got it at a good price, even if it's really just a worse version of the 30L4. It's a fun little flashlight, woefully outdated now I'm sure. I got these primarily for their operation. Two buttons, one which goes to max power, the other which lets you click through the power levels. The flashlight worked fine for a long time. I had been storing it, tailcap unscrewed, without using it for a while. I went to turn it on the other week and the operation was not working as intended. It stays on the lowest setting. If I hold down the Max Power button, it will be at Max Power, but when I release it will go down to low. Same for the cycle/step button. Press and hold, it will display that light strength, but when I release it will go back to low. I can't find any documentation that this is an alternate mode of the light, the batteries are fine, I contacted the manufacturer and they agreed to fix/replace it - though I'm not sure just yet I want to pay to mail this thing to China. Not sure it would arrive or would come back. I was wondering if anyone on here knew what it could be, or if there's some kind of electronic issue I could fix with some solder. I really have no idea what could be wrong. This is my second issue with this line of flashlights, maybe it's because this was a new idea but I'm pretty disappointed! My TX30, also by Eagtac with the same functionality, just stopped working one day. That one was easier to send back and get fixed though. I have not taken this light apart, in fact it looks and feels so well made I think if I tried I'd botch it all!! But I'm interested in learning more and looking into this.

Thank you!!

Bumping to see if I can get any help. I hate having this basically broken flashlight. I could just buy a new one at this point I guess, less aggravating than owning this. I never know how to get rid of my old flashlights.