Low battery warning shows up when you are within 0.6V (or something like that, I cannot remember perfectly) from the 0.001C voltage you configured for your ESS “dynamic cut off” curve.
So getting a “nuisance” warning may simply indicate that your curve is a little high, it might even mean nothing. It will show up at times of moderate to low power use while they may be nothing to worry about. Especially on 15-cell batteries where 0.6V might not be all that much anyway.
Not true. Even with a GX device connected, if you drop below the cut-off curve, it will either switch to passthru (if the grid is available) or turn off (if the grid is off), and if you get close to the curve, it will raise a low voltage warning. The ESS curve replaces the low voltage cut-off.
46.6V in a 15-cell battery is 3.1V per cell, which is somewhere around 15% to 20% SOC. So depending on the SOC at that time of the day, calibration differences, etc etc… it could be normal.