Time is shown as Xa or Xp instead of Xam or Xpm in front of an Event in the calendar

Steps to reproduce:

1. In a calendar create a new event with a specific start date and an AM hour and a specific end date and hour, uncheck the All Day box e.g. Start Date 01.03.2017 03:00 and End Date 02.03.2017 11:51
2. Click Save
3. Observe how the hour is shown before the event name e.g. "3a"
4. Crate a new event with a specific start date, PM hour and end date, hour, uncheck the All Day box e.g. 15.03.2017 21:20 and 16.03.2017 17:35
5. Observe how the hour is shown before the event name e.g. "9:20p"

Expected results: The hours show as Xam or Xpm.

Actual results: The hours show as Xa or Xp.