In brief: Garmin ignores its own settings AutoUpdate = OFF, and despite the settings autoupdates the device.
In details: Today with Fenix 5+ and Garmin Express with all AutoUpdates switched off I was forced to auto update the following way:
My settings and versions were:
F5+ (fw ver5.58beta - complete including all minor files as GPS etc.):
Settings > System > Software Update > Auto Update = OFF
GE (ver 6.9.1.0):
Settings > Schedule > Update Schedule > Automatically download device updates = Never
What happened:
When I opened GE witch F5+ attached, the GE immediately claimed I am on the 6.00 firmware
(which was not true at the moment as in the watch was installed still the beta above)
and uploaded the following ver 6.00 files into the F5+ folder structure:
\GARMIN\GUPDATE.GCD (firmware ver 6.00 file)
\GARMIN\RemoteSW\gup3014.gcd (sensor hub ver 2.30)
I was able to stop that process by:
1/ copying these two files above to the PC backup folder and
2/ delete them from the device before I dettached the device, so I remained on my untouched firmware as above.
My settings - to not AutoUpdate stayed in the devide as described above.
After that I reconnected F5+ again and GE did the same - (and I willfully allowed the update).