Strange one here - My clients are running Exchange online and have recently configured MDM for their mobile devices so that users need to be enrolled to access corporate data from their phones (emails, OneDrive and so on). They created a security group and have restricted access through this group - anyone wants to enroll is added to the group. Some of the users who are using personal devices decided not to enroll so they are not in the group and do not have access to emails on their phones.
However, one user who has not enrolled is still receiving emails on his phone. We have checked the group membership multiple times and the user is definitely not enrolled - company portal needs to be installed on the phone but he does not have it. Any ideas why this may be happening? it is an older Android phone that the user has.