One reason for the erratic ejection pattern could be due to a bent ejector. Colt says this can happen when magazines are seated too hard.
...the intermittent, but frequent, ejected case to the forehead. This seemed to occur across a variety of ammunition brands and loads, but was more prevalent with lower pressure rounds. While cleaning the pistol between range sessions, I inspected the ejector and noticed that it has a distinct curve toward the ejection port. Now, that could very well be how it is designed – or it could be bent. Colt indicates that the extractor should be checked after about 5,000 rounds and possibly adjusted. Regarding the ejector, Colt mentioned that this has been observed in their 9mm guns before and can depend on the magazine being used, and if they are really slammed up into place with the slide locked back.