I think that it was three unsatisfactory that he mentioned at that time. It was part of a long informal discussion that we had with them during an Active Shooter preparation assessment they did for us here following the protests and sniper shootings back in 2016. As I recall it was a combination of insufficient expansion and / or penetration from the small pistols after going through very heavy clothing, which did not solicit the expected/desired response from the target. I work with them, but not for them, so I am sorry but really don't think that I should put up here the exact specifics of what I was told.
From what I have heard since then they are pleased with the 127 Ranger and are still using it, but we have not discussed any shootings with it. I think that a lot of their ammunition selection process tends to be weighted heavily in favor of good performers against vehicles. All the discussions we have had about ammunition since then referenced performance against auto glass, doors, hoods, etc. For example I have been told that they don't like low recoil (velocity) buckshot because of poor vehicle penetration. I need to try to get them to let me shoot some Flight Control #1 at some junkers up there one day just to see how that super tight shot column hitting together offsets lower per pellet energy.