For anyone looking for a work-around we successfully re-purposed an older Facebook app ID with Graph API v7.0 for use with Auth0.
If you have an older Facebook app (< v8.0) that is used in a test, qa or staging environment it might be an option for you to re-purpose it for an Auth0 connection that is affected by this issue.
Keep in mind that switching away from your re-purposed Facebook app at a later point could be problematic depending on your use of Auth0.
Also, older Facebook apps that are not in use will most likely require re-activation of Graph API access and will force you to upgrade it to v8.0 so a candidate Facebook app is one that has somewhat recent usage.