There's nothing wrong with that ejector. Some recent production Glocks, Gen3 and Gen4 9/40/357, have had a problem with erratic ejection caused by the extractor not firmly holding the rim of the spent casing to the breech face. It can be caused by an out-of-spec extractor which can simply be replaced, but in some cases using an extractor known to work properly in another gun doesn't fix the problem. I had a Gen3 G27 that had the problem, replacing the extractor with one known to work properly didn't fix it. From what I can tell, Glock machined the slide incorrectly, the cut-out which holds the extractor is positioned too far forward, and the forward portion of the cut-out wasn't cut deep enough into the slide. Using the new .40 28926 ejector fixed the problem.
The new ejectors, 30274 for 9mm and 28926 for .40/.357, change the ejection enough to fix the problem by raising the case mouth of the spent casing higher to better clear the ejection port.
If your gun doesn't have the ejection problem, you don't need the new ejector.
The newest Gen4 trigger housings sold by Glock, part numbers 30275 for 9mm and 28927 for .40/.357, will have the new ejectors in them and it should only be a matter of time before retailers get them in stock. If you want to use the new ejector in a Gen3, it's a simple matter to take the ejector out of the Gen4 trigger housing and put it into a Gen3 trigger housing.
For a short time Glock was using the new ejectors in Warranty cases to fix the ejection problem in Gen3's, they have recently stopped doing that and all they'll do now is replace the extractor and tell you to stop limpwristing. Gen3's come from the factory with the old ejectors, 336 for 9mm and 1882 for .40/.357. Gen4's with a test-fire date after 10/10/2011 will have the new ejector installed in them from the factory.