Milestone Not Showing in Calendar View and Missed Deadline

I used Milestone for the first time this week. I made two existing tasks Milestones. I was looking forward to seeing milestone met when user completed the task. However, user relies on her calendar view to see what is due, and the Milestone shows only a symbol (?) and not the name of the milestone task on the calendar.

As a result, she missed her deadline.

What are the product expectations for the behavior of milestones when presented in the same places regular tasks appear?

They are supposed to show up in the Timeline apparently but not in the Calendar?