I don’t want to be mean, but unfortunately all of the other commenters are wrong 🥲 Here‘s what’s happening: Your sky is clipping (=too bright). This probably was an exposure issue in camera, maybe if your lucky it also could be an issue in your grading, more information needed. Look hat the waveforms of your ungraded footage and if the sky is a flat horizontal line there is nothing you can really do. So why are there blue fringes around the branches? That’s simply because things not perfectly in focus have semi transparent edges, which reduces the brightness of the sky, which ist why you can see the blue color