Sharp outline around Sim bodies despite ultra quality settings

Hello everyone. I've had this happening in my game for a while and I've finally decided to ask if people had any idea what might be causing it. I've attached images, hopefully you can see what I'm talking about. There's an area in the exact shape of my Sim that seems to create an "outline," primarily around the shoulder area, where it's much sharper than the rest of the background. I've also included edits of the screenshots where I've drawn over the outlines. This has been happening for over a year despite my game settings being on ultra settings/the highest possible. I've tried searching Google for this and haven't found anything that might solve it. I've also tried it with no mods/cc (clean mods folder), and the issue persists, just to a lesser extent. In addition, I've tried repairing my game. I just figured I'd see if anyone knew what was going/has also encountered this, and how I could fix it. Thank you.