Canon EOS M6 Mark II Advanced User's Manual page 501

The date, time, and time zone settings may be reset when the camera is stored
z
without the battery, when its battery becomes exhausted, or when it is exposed
to below freezing temperatures for a prolonged period. If this happens, set
them once again.
After changing [Zone/Time difference], check that the correct date/time are
z
set.
Auto power off time may be extended while the [ 5 : Date/Time/Zone] screen is
z
displayed.
Date/Time/Zone
501