Android devices running Android OS 5.x (Lollipop) that are encrypted prior to enrollment will continue to be prompted to encrypt the device after enrollment despite already being encrypted.
Navigate to the screen lock settings and enable the option that states “Require PIN to start device”.
This issue has been given identifier AAGNT-173681. This issue is not reproducible in Android 6.0. Our product team is working with Google to confirm the resolution of this issue in an upcoming Android release.