Marrakai is probably correct.

However, you might also check the extractor and extractor spring. Several things can happen there that can cause the problem you describe:

1} Weak extractor spring; the extractor sort of slides the case head to the left as the bolt is opened, allowing it to ride against the smooth left action wall until it hits the ejector screw. A weak extractor spring may allow the case to be withdrawn from the chamber, but not have enough "pushiness" to maintain tension on the case till the rim hits the ejector making for wimpy ejection, partial ejection, or no ejection at all.

2} Dirt under and around the extractor/extractor spring; this acts to in effect create the same scenario as #1} above. I've seen Lee extractors that had a "varnish" buildup of years of grease and oxidized oil mixed with dirt and dust and had extractors that simply did not operate properly, giving the impression of a weak spring. Once cleaned, all was well.

3} Too short or burred ejector can as Marrakai says be causing you the problem. Probably is that. however, you might check to see if the ejector was once removed and linseed oil or grease or action paint, etc got under the ejector screw head. This will have the function of "shortening" it by not allowing it to seat all the way when replaced and can cause ejection problems normally associated with a worn ejector.