Right, I hadn’t measured the standby drain past 3 mins to see if it dropped down. I have just measured it, and can confirm it drops down and stay at ~100-110 uA on my sample, with no more jumps up to ~1.82 mA.
I have tried the powerbank feature after auto-lockout engages, and it works no problem. So you are right, the jump-up in current to ~1.8mA every few seconds (before the lock-out engages) can’t be due to powerbank feature.
On the other hand, once the auto lockout does engage, that means the standby drain for this light (without the indicator feature on) is actually not that unreasonable for the class - a little under 5 and half years for 5000mAh cell to drain at the post-lockout ~105 uA average.