Why number of "Non-user mailbox" protected by Collaboration Protection exceeds the purchased license size?
Non-user mailbox will not be counted directly to the license size, like 1 license: 1 mailbox. Instead, it will be be counted as 1:2 ratio for now.
For example, if customer has 5 licenses, therefore maximum they can protect 5 user mailbox and 10 non-user mailbox.
Please take note that shared mailbox is considered as a non-user mailbox.
Article no: 000042878