Why is there a weird section of desaturation in some of my photos?

So as I was editing some photos in Lightroom Classic I noticed this weird patch that was desaturated. It doesn't show up when I import the photo but as soon as I start editing or applying any presets it shows. I'm not sure if it's something to do with the RAW file (I use Canon so it's a .CR2) Has anyone had this problem before???