Good find.
In the manual it shows how to remove the belt from the c pillar and engage them next to the seat, but there is no instructions on how to remove the belt again to restore back to this position. I cannot figure out how to remove the belt from the seat.

But it looks like this is possible and the belt can be stored in the pillar when 3rd row is not used. Thanks for this find.

Now, if someone can figure out where the release button is.