Long Video Podcasts lag/stuttering on Lumia 920

[FONT=arial]as much as I would like to love my new Lumia 920, I have a major problem related to the playback of long video podcasts:[/FONT]
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[FONT=arial]Subscribed to the following video podcasts from the Twit network:[/FONT]
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[FONT=arial]All about Android: http://feeds.twit.tv/aaa_video_small[/FONT]
[FONT=arial]Before you buy: http://Feeds.twit.tv/byb_video_small[/FONT]
[FONT=arial]Windows Weekly: http://feeds.twit.tv/ww_video_small[/FONT]
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[FONT=arial]My observation is that after a while of watching the video/audio playback starts to stutter. The longer the playback the shorter the frequency of interruptions. Almost not watchable anymore. Quite weird that I do not have the problem with other long video podcasts or any audio podcast. Also movies (mp4) transfered to the device playback without any troubles.[/FONT]
[FONT=arial]Tried already various podcasting apps like WPodder, Podcast, Bringcast, PodcastLounge and iCast, but doesn't seem to be related to the podcast app, but more with the WP8 OS itself (and probably its handling of specific video codecs?).[/FONT]
[FONT=arial]Also, never had this problem with my older WP7.5/7.8 devices like Lumia 800 which synchronized the podcasts via Zune desktop.[/FONT]
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[FONT=arial]Has anyone observed the same issue? Would love to get some feedback.[/FONT]
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