On Samsung Galaxy S6 and S6 Edge devices running Android 5.0+, the EAS identifier reported to mail servers is different than the EAS identifier reported to MDM. When used in conjuction with a SEG or PowerShell deployment, this can result in these devices being incorrectly denied access to email.
Affected devices will report as unmanaged in the email management dashboard. If the configured compliance rules allow unmanaged devices to connect to the mail server, then affected devices will continue to receive email. Additionally, these devices can receive email if manually whitelisted from the email management dashboard.
This issue has been given identifier AAGNT-174482. Samsung has identified this issue and will be releasing a fix as part of their next major release. The specific build number will depend on the carrier. Please contact your Samsung representative for more information.