We are aware of an issue with iOS 12 devices not prompting for the password of assigned email addresses. When viewing the Mail account under Settings > Passwords & Accounts, the only option available is to "Re-enter Password"
How to resolve
1. Initiate a temporary change under the "Email" tab of the blueprint and hit "Save Settings". *Note that this will require all devices associated with the blueprint to re-enter the password for their mail account. If there is a desire to avoid this, a new blueprint can be created to isolate any device running into this issue.
2. Once the device Inventories to receive these changes, we should see the assigned mail account prompt for the password.