External PNG graphic not displaying (Geoserver 2.13)

Question

I have recently upgraded from Geoserver 2.11.0 to 2.13.1 and have found my external graphics for point layers are not displaying (they revert to a default grey symbol).

Is there anything wrong in my code, or has anything changed between 2.11 and 2.13 which might be causing problems? Inaccessibility problems for Geoserver to online resources?

An example of my xml is below:

<?xml version="1.0" encoding="UTF-8"?>
<StyledLayerDescriptor xmlns="http://www.opengis.net/sld" xmlns:ogc="http://www.opengis.net/ogc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.1.0" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.opengis.net/sld http://schemas.opengis.net/sld/1.1.0/StyledLayerDescriptor.xsd" xmlns:se="http://www.opengis.net/se">
  <NamedLayer>
    <se:Name>cctv_cameras</se:Name>
    <UserStyle>
      <se:Name>cctv_cameras</se:Name>
      <se:FeatureTypeStyle>
        <se:Rule>
          <se:Name>Single symbol</se:Name>
          <se:PointSymbolizer>
            <se:Graphic>
              <se:ExternalGraphic>
                <se:OnlineResource xlink:type="simple" xlink:href="http://maps.runnymede.gov.uk/website/maps/png/community/cctv_cameras.png"/>
                <se:Format>image/png</se:Format>
              </se:ExternalGraphic>
              </se:Graphic>
          </se:PointSymbolizer>
        </se:Rule>
      </se:FeatureTypeStyle>
    </UserStyle>
  </NamedLayer>
</StyledLayerDescriptor>

Answer 1

Works fine on my local machine with 2.13.0, but does fail with 2.13.1, I've filed a bug.