Whatever it’s source, it looked GREAT in the just previous version of MSFS (except perhaps for the “untreed” terrain being a little too grassy green and soil looking a little too colorful). It’s the last area I flew over in the previous MSFS version, I’ve flown over it many, many times, and I have 100 Gb of rolling cache. So whatever generates that scene, it’s drastically changed from the previous versions of MSFS. It has never looked so bad. Previous versions the river was mostly in its proper place and at least a decent amount of bare rockface showed on the cliffs on the right side of the river.
See 2nd, 3rd, & 4th pix in this post: I9 9900K + RTX 2080 TI = Low FPS ?!?! - #128 by JALxml for comparison. The 4th picture is REAL LIFE.