I was looking at another thread that mentioned Karh polishing an ejector related to failure to return to battery. Any details on what to look for?

I have a CW40 which I like the size. However, when new it would have about an 80% failure rate to return to battery. I sent it to Kahr, and have not had the same issue. However, the firearm still feels not-quite-that-smooth in between each shot when returning to battery. I don't experience this on any of my other Kahrs, including my T40.

Could someone tell me what to look for, or feel for? What side should I prioritize smoothness? I can feel a tiny burr (too small to see) when running my nail on the side, right where the wedge area drops off to the side of the pistol. Anyone familiar with ejector polishing? I know how to feel for burrs on my knives when sharpening and should be able to take it off without problems, but I was hoping for someone more experienced to tell me what to look/feel for, remedies, or even show pics if they had any.