At present reporting on access to secrets stored in keyvaults is only easily deploy-able on users that a members of the underlying AD tenant. For invited users the logs only record the object ID and not the username - meaning that in order to generate reports on secret access additional scripting is required within the code to perform a lookup to gain the details that are already in the Tenant AD and populate a variable to be used. As the information is already in Azure AD it would be more elegant for this heavy lifting to be done by the platform.