Artefact in IPTV stream

I use Rasp Pi 2B with OpenElec 6.0.3 and Kodi. I also have hardware acceleration for mpeg.
Generally IPTV streams are well received. However, the following high quality stream shows an artefact, not with the vlc or Kodi player on my Windows PC, but with the Pi:
http://lb-at5-live.cdn.streamgate.nl/at5…28000.m3u8
Stream is from local TV station Amsterdam.
The artefact is in the lower part of the video and shown as a picture in:
http://imageshack.com/a/img924/9823/KJlug6.jpg
The video plays without stuttering.
I am curious what the cause might be for this artefact: limit of the possibilities of the Pi? Codec? Wrong setting in OpenElec or Kodi?