iPhone backup setting in iTunes keeps changing to iCloud
For the last couple of weeks of the new year it seems that when I go into iPhone Settings in iTunes on my iMac, the radio button for Automatically Backup has been switched from This Computer to iCloud. As such, my iPhone never gets backed up to the Mac unless I hit the Back up Now button.
Every morning I go to the Settings and switch it back to This Computer, and hit Apply/Sync/Done (whatever the button says at the time).
And the next time I plug it in via Lightning cable, it's set back to iCloud.
In fact, once a manual "Sync" is done, the setting will switch itself back to iCloud :(
On the iPhone, iCloud backup is turned off
2017 iMac 5K 27" - macOS Mojave 10.14.6
iPhone 11 64GB - iOS 13.3
Apple Lightning cable plugged in to the iMac
iPhone 11