'e' format character prints timezone twice when displaying from and to dates

If using the 'e' format character in a date format to display the timezone then the timezone is displayed twice when the 'from' and 'to' dates are displayed.

For example the format:

l j F Y - g.ia e

Displays the date as:

Friday 27 September 2013 - 3.00pm to 9.00pm Asia/Kolkata Asia/Kolkata

The output HTML for this is:

<span class="date-display-single">
  Friday 27 September 2013 -
  <span class="date-display-start" property="dc:date" datatype="xsd:dateTime" content="2013-09-27T15:00:00+05:30">3.00pm</span>
  to
  <span class="date-display-end" property="dc:date" datatype="xsd:dateTime" content="2013-09-27T21:00:00+05:30">9.00pm Asia/Kolkata</span>
  Asia/Kolkata
</span>

Could this be because the $timezone variable is being output inside 'date-display-end' by the theme_date_display_range() function in date.theme?

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Currently using a workaround of using 'T' format character instead, which displays the abbreviated timezone and doesn't duplicate:

Friday 27 September 2013 - 3.00pm to 9.00pm IST

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