Strange increments near regional domain's border

When I made 3dVar with in-situ measurements (VertInterp operator) for the RRFS-CMAQ C401 domain, some strange positive increments appeared near the domain’s borders/corners where no observation exist nearby. What should I do to resolve it?

As I think he has discussed with you, @CoryMartin-NOAA has implemented a fix for this that involves filtering out obs outside of the domain. I’m mentioning it here for the benefit of the community