I went to the range again today, this time with the Witness extractor in the AR24. I brought 50rds of Geco 124gr FMJ, 50rds of Federal American Eagle 124gr FMJ, and 50rds of Remington UMC 115gr FMJ (nickel cased). The pistol ran 100% except that twice the last case was left sitting above the magazine after firing a mag of the Geco ammo. There were no stove pipes. In a real world situation that wouldn't have hurt anything as the case would have fallen out when the magazine was dropped, but it's still not right. Overall, the ejections definitely appeared much better. It was not possible to see most cases fly from the pistol, although I could still see a few. The Geco ammo went straight out to the right. Oddly enough, the Remington ammo went to the right/back with the most velocity. The strange thing is that it's not at all a hot load.
What I know for sure now is that the Witness extractor certainly didn't make the problem worse. It likely improved things. I'm going to reinstall the original extractor and try things again. If the problem comes back, then I'll give Armalite a call.