We have a number of devices in the field which are running the same firmware. On a few on them we see the battery start to discharge even though the device has a Vin source. We are using fuel.getSoc() to return the battery level periodically. The common denominator is that these devices have a low cellular signal level. We are not sure that the 2 are related but don’t know what else could be causing a drop in battery and then recharging.
In the picture below you will see a few of the devices.