Does 'Battery Protection Mode' turn on automatically?
I got a response from our support contact at Esper. This is apparently a Lenovo feature.

Lenovo &quot;Battery Protection Mode&quot; will be automatically enabled if the device is continually charging for around 7 days.
This is a feature designed by Lenovo to reduce excessive battery heat and degradation.
While plugged in the device will stay at a charge level of about 60%, and will slightly vary at times but should dip no lower than 50%.