Hello Garmin support.
I've the 12 hour/24 hour setting issue before as well, then after a few days (today) later, my forerunner 235 always auto restart when auto sync with my android phone, even I've soft/hard reset my watch to try, or reinstall GCM with my android/restart my phone. Still no luck.
And I've found that my watch getting a wrong time as well, it seems cannot get the GPS signals to sync time. This makes me need to manual set time to fix it temporary. Please help.
Cheers