Weird in-camera artifacts with shallow DOF

Getting this strange effect on my background when a use a shallow DOF in UE4.26. It’s like I can see the outline of my background even though it should be blurred.

Looked through a bunch of other help forums, couldn’t find anything that helped. I did set my anti-aliasing to “None” in my project settings based on some answers, but didn’t do anything. Would seriously appreciate any help with solving this!