Update this is a Windows Defender issue not a database issue. http://jtpedersen.azurewebsites.net/index.php/2017/07/06/windows-defender-issue-on-windows-server-2016-with-dpm/
This will be short, There seams to be a bug in the DPM 2016 database once it reaches a certain size or number of recovery points. We have 2 setup around the same time and both failed within 2 days of each other. The symptoms where backups just standing still not doing anything and if i open resource monitor of perfmonitor it would be slow and sluggish.