TL:DR

On the Fenix 7s, the cancel confirmation dialog used by Communications.startSync doesn't seem to work correctly. However the cancel confirmation dialog used by Media.startSync does work correctly.

Scenario

On the Fenix 7s, if you use Communications.startSync to begin a sync and then use the back button to cancel, the system will pop up a confirmation dialog.

For clarity, I will call this NEW CONFIRMATION DIALOG, and it is characterized by having a checkmark icon at 30 degrees and an 'X' icon at 210 degrees.

If you click either the checkmark or the 'X' on NEW CONFIRMATION DIALOG, it will not appear to have an effect. In other words, the Syncing screen will continue to show.

I suspect that the app may be crashing similar to https://forums.garmin.com/developer/connect-iq/i/bug-reports/confirm-dialog-exits-app-unexpectedly-for-fenix-7-audio-apps

In contrast, if you use Media.startSync to begin the sync and then cancel, you will see OLD CONFIRMATION DIALOG. OLD CONFIRMATION DIALOG is characterized by a list menu with items 'Yes' and 'No' present. Selecting OLD CONFIRMATION DIALOG items works correctly.

Comparison to Other Devices

On the Forerunner 955, the cancel confirmation dialog works for both Media.startSync and Communications.startSync