When you have deployed Veeam Backup for Microsoft Office 365, use snapshot-based retention and storing data on a Jet Database-based repository then your solution might mistakenly remove restore points of Exchange data that are still valid.
This applies to versions 5.0 Day 0 Update and earlier down to version 3.0 GA.
You can check your current build number by clicking Help and Support > About in the main menu of the Veeam Backup for Microsoft Office 365 console.
If you are running version 5.0 GA please upgrade to version 5b or wait for the hotfix we are preparing.
If you are running version earlier than 4c please upgrade to version 5b or upgrade to version 4c first and install cumulative patch KB4099.