I changed no settings and system has been running for about 9mo. Woke up today and the MPPT was making 0w. I noticed it was saying battery was -18c. I have no battery temp sensor or anything connected to the aux port of the shunt. I disabled low temp protection and it started up. I reviewed the history in the mppt and at 20:30 the shunt started reporting -18c to the mppt. After about 3min of the system charging the temperature being reported went away. Why would this temperature just randomly show up?