Prayer idol in the air in the kaer Morhen (The Witcher 3: Wild Hunt)

For the 10th time going through the game and then suddenly stumbled on a prayer idol, hanging in the air. I remember that on Skellige there's a mini-quest with prayer idols near Harviken, and suddenly stumbled in the heart of the kaer Morhen. Does anyone know what this quest or is it just a sham?
Is here:
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When you approach lights action, but prayer does not pass, tried to beat airdam for activation, as is the case with portal stones, but still nothing. To it a little bit hard to get, as you can immediately slide down the slope and break, so I suggest you persist - if someone decide to watch.

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