Rivian showing sleep losses as negative

On my Rivian's ElectraFi feed, the Sleep tracker often shows Loss and Battery as negative. Does this mean that ElectraFi checked the stats at the start of the sleep cycle and at the end, and actually found the battery SOC *increasing* during the sleep? It could be possible - maybe the BMS is inaccurate while not asleep, but while asleep the BMS has more time to accurately measure battery state, and the final estimate is actually higher.