Using Ola Hallengren's succeeds to take full backups but fails to take a differential

I take weekly Full backups (all my databases are in Full recovery model) on Sundays and then schedule the Diffs to run nightly (except on Sundays). Looking through my logs I see this: > Cannot perform a differential backup for database "DBNAME", because a current database backup does not exist I do have the VSS Writer running but have no 3rd party tool that I know of running that should "invalidate" the Sunday full backups. If I manually run a Full backup then run a Diff it works just fine. These machines are VM's in Azure running SQL Server 2017. The strange thing is on my test machine it works with the same setting (VSS Writer enabled). I'd rather not disable the VSS Writer if do not have to. Any thoughts?