A fellow brave soul (pun not intended).
I'm notorious for running my vehicles on low fuel, think i filled up the X5 the other day showing 36kms but it was dropping like a rock the last few minutes. Lowest I got on the XR was 7km before i chickened out, lol.
In my case there's a little bit of method in the madness. You're supposed to run it below 10% once in a while and run it up to 100% once in a while and leave it plugged in for a bit, to encourage the BMS to keep the cells balanced and help the GOM guess more accurately. I had it up to 100% before setting out for Lindsay yesterday and it was plugged in at 100% for a couple hours, and now it's around 10%, plugged in, but "delayed charging" (it won't start charging until sometime overnight).
In the hour and change between coming home and plugging it in (just now, because I won't be driving it any further today), the GOM increased from 39 km to 46 km, and the state-of-charge bar graph turned on the next bar without being plugged in (!!), so it's thinking about it. Also, coming home from Belfountain only used 9 km to drive 22 km according to the GOM, and it was already on orange low-charge-level-warning there. (It is somewhat downhill, overall)
This is all "nature of the beast". The voltage on this type of battery stays flat for a large part of the charging curve, making it hard for a cell voltage measurement to correlate to a charge level, and if you habitually stay in that range (which is my normal practice - charge limit is normally set to 80%) the BMS slowly loses track of exactly what the state-of-charge is due to inherent inaccuracies. Then it starts looking like you are losing range, even though you're not.
Solution ... really simple ... exercise it once in a while.
An inaccurate BMS with unbalanced cells caused by not doing this, won't cause any actual operational problems. It'll mostly just make the GOM display less range than you've actually got.