Freezing temps and Lifepo4 batteries is a not a good combo. For the life and best function of ANY Lifepo4 chemistry battery you should keep them above freezing. Sounds like you are taking action to fix this.
Per the EG4 manual:
There are several thermal sensors to monitor cell temperature. If the temperature of any
cell is less than 23F or greater than 158F, the BMS will disconnect the battery module terminals to terminate
charging. The BMS will automatically reconnect the battery module terminals and allow charging to resume
after the temperature returns to within 32F to 140F.
If the temperature of any cell is less than -4F or greater than 167F, the BMS will disconnect the battery
module terminals to terminate discharging. The BMS will automatically reconnect the battery module
terminals and allow discharging to resume after the temperature returns to within 14F to 149F