We are aware of an issue that has been occurring when blank updating a user within a GP phone User Policy in Portal, their mailbox size is being reverted to 4GB as opposed to matching the mailbox size dictated by that User Policy specifically when larger mailbox is toggled on. These GP Phone User Policies were manually created in the database and were not created through the Portal UI which is causing the conflict.
Latest updates and guidance:
This is being investigated as part of problem record PRB0194126.
If you experience this issue, go to the User Policy via the user Policy Management page, add a user to it and then click update, This should correct the issue. If you are trying to correct this for a large user policy it can take some time. Please wait at least 1 hour and if the issue persists raise a request with the NHSmail Helpdesk (email@example.com) for further assistance.