Error Registering a Hub Site

Hello, We are getting an error registering a Hub Site. We get an error in the GUI, in SPO PowerShell or PNP PowerShell:

Register-SPOHubSite : The property 'EnforcedECTs' does not exist on type 'SP.HubSite'. Make sure to only use property 
names that are defined by the type.
At line:1 char:1
+ Register-SPOHubSite https://CONTOSOapac.sharepoint.com/sites/CONTOSO_CN_IT   ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Register-SPOHubSite], ServerException
    + FullyQualifiedErrorId : Microsoft.SharePoint.Client.ServerException,Microsoft.Online.SharePoint.PowerShell.RegisterS 
   POHubSite

Does anyone have any ideas?

We're probably going to 
Thanks
Laurence