Hi @Un-Known,
If the user does not have any hold enabled, please run this cmdlet and wait for some time to see if the server can purge the items in the recoverable items:
Start-ManagedFolderAssistant -Identity "user"
If this does not work for you, to me this issue may need to be further troubleshooted from backend.
Please consider contacting support for help via opening a service request in Microsoft 365 admin center.
Thanks for your understanding.
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