I'll SWAG idle JK power consumption to lie somewhere between 0.3 watts and 2.0 watts in idle, because the Bluetooth radio is active at all times. On my "12v" battery pack, current supporting those power figures would range between .02 and .16 Amps. It is a bad assumption, on your part, to assume that my current shunt/coulomb counter modules are unable to track such small changes in VA over a period of days or weeks. With effort, I could measure the JK consumption with a pair of "before" and "after" versus after shunt/coulomb counter modules, but it's 99% irrelevant to my original complaint.
What you accuse to be a mere "guess" at SOC was confirmed upon recharging the battery pack, with the coulomb counter showing a bit under 80A taken in before "full" charging voltage was reached (on all cells in good balance, due to JK's high balancing current capability).
Although a lead-acid battery stored at STC temperature will lose capacity quickly, LFP batteries discharge at a much lower rate. The self-discharge rate of a particular cell varies according to the original storage SOC and temperature, along with the characteristics of the particular cell in question. But unless stored HOT, a properly constructed LFP cell charged to at least 50% SOC will last for months before going low from self-discharge.
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Over a period of less than 2 weeks, your misstated "issues", even if present to a tiny degree, would be irrelevant to my original complaint: The JK App shows quickly rapidly dwindling capacity numbers, clearly becoming significantly "wrong" in just a couple of days, and it degraded all the way to "nothing left" when the battery pack was actively used and then left at more than 50% full.