Microsoft announced. that the behaviour for the Group Policy Allow syncing OneDrive accounts for only specific organizations will be changed.

Currently, if you have enabled the setting but have not specified a Tenant ID, the setting will Block all organizations.

With this change, having the setting enabled without a Tenant ID being specified will have the same effect as if the feature were disabled.

You do not need to do anything unless you were intentionally relying on the behaviour of enabling this setting with no Tenant ID in order to prevent OneDrive from syncing with any organization. In that case, you should mark the setting as disabled rather than Enabled with a blank Tenant ID.

These changes start beeing roll out mid-May 2020 and will be completed in early June

Resource

Microsoft 365 admin Center: MC211659