Inaccurate "your device is using mobile data" error dialog shown when connectivity is unavailable

Steps to reproduce: Option 1. Try to back up manually in airplane mode. Option 2. Try to back up manually with a VPN that is disconnected or for which Seedvault is excluded, and it is set to "Block connections without VPN" in the system. Option 3. Try to back up with a firewall blocking Seedvault.

Expected result: Error message says something correct, e.g. "Seedvault couldn't get online. Check if your device is in airplane mode..." (something like that).

Actual result: Inaccurate error message about being on mobile data. And adjusting backup scheduling to allow mobile data as the dialog suggests, gives the same dialog.