The female newsreader on the Eastern Express channel, based in the Urals city of Chelyabinsk, read an upbeat item about new medical equipment in regional hospitals, only for her broadcast to be interrupted by an item saying that "the epoch of Putin... Brought Russia criticism from every international rights organisation."
The broadcast was on July 31 but the story only caught national attention this week after a video was posted on YouTube.
The channel had previously aired glowing footage of pig farming and regional governor Mikhail Yurevich, a member of ruling party United Russia, making clear its pro-Kremlin loyalties.
It would be unthinkable for Russian state television to air a report critical of Putin.
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The planted news item went on to link Putin to the 2006 murder of journalist and Kremlin critic Anna Politkovskaya and attack corruption that had reached "unimaginable heights".
It launched into the terrorist attacks at the beginning of Putin's presidency, saying they raised his approval rating, before the channel abruptly switched back to footage of the governor, with no explanation.
The head of Eastern Express channel, Valery Shagiyev, headed a regional supporters' group for Vladimir Putin during his 2012 election campaign.
Shagiyev called the stunt an "act of hooliganism" in comments to regional news site Uralpolit.Ru, saying the director responsible would be sacked.