Members not being added to groups in 7.4.4

We have a provisioning policy that adds a user to an Azure (M365) group if their department equals IT.

For some reason the policy is applying, the logs suggest the member has been added to the group however when you check in Azure/O365 admin center the user is not in the group? 

Event ID 1525 is as follows:

Members added to group.
Operation GUID: 16e886d5-1907-4ef4-86fa-67aacb8b0d52
Group name: it
Parent container: Configuration/Azure/domainname/Office 365 Groups
Group object GUID: 818d0f90-2297-4e0b-bc11-2637bbfb129c
Members:
<SID=010500000000000515000000BCD45227EB9548634BDD90BDC4040000>

I know its not permission related as i am able to add users to the Office 365 groups from the ARS Admin web page so this issue is purely related to provisioning policies/workflows. 

Anyone got any ideas on why the user is not being added?