This thread is similar to how the Backup Not Happening thread started but as that is now covering all sorts of problems I have started a new one.
I discovered daily backups were not running. I could manually run a backup ok and backup to Google Drive.
I noticed in settings the time now showing in the status window was not the local time.
Looking in to this it seems that wordpress likes to use the UTC time and not local time. So if you use date_i18n to get the current date and time you aren't necessarily getting the local time - your getting UTC time always.
So here in Autralia I'm looking at the settings page on Sunday but it thinks it's Saturday. If I now go and choose daily backup it nicely puts in start date of sunday at 00:00 . The problem is that was hours ago and so it will never run.
There may also be a similar problem if a backup does run if it then uses the UTC time to schedule the next one ?? (not sure how it works).
See here for an idea on using local time.
I think using local time somehow is the way to go.
Appreciate your efforts on the plugin. Backing up to google drive is terrific!