A very small number of users globally have reported the sensor reverted to degrees C from degrees F. 

A repeatable pattern across the user base has not been established. At the moment we suggest to double check Configuration data (default settings up initialization). This was reported to have helped based on user feedback.

Information can be found on pages 59 and 60 of the Endurance manual:

Eds names the tags for config data and they are stored alphabetically, so it will not be the first tag in the list.

If  it is displayed as a decimal number, it will be 67 for deg C and 70 for deg F

HEX: 43 for C and 46 for F