it says here "The investigations are still ongoing and the findings will be intimated on [their] conclusion."
it's clear in the video that the Israeli soldier is cutting a tree located behind the fence, therefore inside the Lebanese borders, it doesn't take a genius to figure that out.
In the article you link UNIFIL, who one can not accuse of being partisan to Israel, specifically state the tree was on the Israeli side. I'm not sure what the video shows, and where exactly the blue line is. I know what UNIFIL are saying, though.
But I'm willing to wait for the final conclusions of the investigation, I promise to accept the results, do you?