Messages sent to groups are not displayed properly in email notifications

STEPS TO REPRODUCE

Preconditions: Message Stream is enabled and Mail Sending is configured in Administration

1. Login as Admin
2. Create an user (e.g. U1)
3. Create a group (e.g. G1) and add the user to this group
4. Login with the user
5. Go to Notifications Settings and set Message Stream toggles to ON
6. Login with Admin and send a message to the group (G1)
7. Trigger the 'Notifications Daily Email' from Scheduler.WebHome
8. Login with the user and observe the email received

EXPECTED RESULTS

The message sent to group G1 is displayed properly in user's email notification.

ACTUAL RESULTS

Instead of sender's username and message, some (code) strings are displayed in the email.