Hi,
we upgraded our Jira to version 5.1.2. Since then the Activity Stream shows an unusual time format on all entries not made on the same day. Todays times are displayed normal but as soon as the entry is from yesterday or any other date in the past the time format looks like this:
Date at kk:mm:ss z (kk being the hour but no digits being displayed - see screenshot below).

Any idea as to what is causing this issue? How can we fix this?