To resolve the issue of a SCIM user not appearing within a SCIM group, you can restart provisioning within your Entra ID. This will restart the provisioning service for all users and groups and remove any existing watermarks.  

The process can take some time, so please allow up to 24 hours before checking on the group again.

The users should subsequently appear within the group as expected. If this is not the case, please don't hesitate to contact our Support team.