Restore from Google backup not given as an option during reset

[Android Central Question]

I had to do a factory reset on my Oppo R7g (Color OS v2.1.0i / Android 5.1.1) and have obviously lost all of my settings so I need to restore them. I have been using the automatic backup to google feature and if I go into Google Drive I can see the last backup was a couple of days ago. When I reset the phone (and I have tried this multiple times now) I do not receive the prompt to restore from a Google backup. My understanding is that once I sign in during the setup, I should see a "Which Device?" page that lets me select the backup. I do not see anything like this when signing in during setup. The backup definitely exists because I can see it in my Drive. How can I restore this??

Thanks.