Have you checked the trigger pack to make sure there is minimal gap between the two sides holding the ejector lever. You can do this by removing the lower and trying to push the tip of the ejector lever left & right. If you're getting too much lateral motion, you should remove the lever and compress that internal tab to make the fit tighter. It still needs to move up and down freely though so don't compress it too much.
This is probably the case if the lever tip is binding on the right side of the groove. Or the left side if you've flipped it over to look at it.