Vault folder structure view

Hi

The original problem started with a shared mailbox where it's vault folder structure (via Search Vaults) could not be viewed, but the team members could search for the mail items (access is controlled by a security group). Then i noticed some old NT accounts in the folder permissions so I removed these performed a manual folder sync and added myself directly to the vault and I could see the folder structure however the affected team member still can't.

I added them directly like I did myself and synced all folder permissions in VAC and still doesn't work for them. I tried with another 2 colleagues of mine who never use this mailbox and they have the same problem yet I can still see the vault folder structure.

We're on 12.5.3, anyone seen this issue before?