The rifle where the casing is hanging on the extractor...I would first check the extractor for burrs, and inspect the ejector to insure that it is operating properly. Checking the ejector is easy...put a casing under the extractor, and when you let go of the casing, the ejector should toss it out from under the extractor. The extractor should not have burrs on it and should hold the casing when the case is pointing as if it were in the bore, but release the casing once the case mouth clears the rear of the chamber.
Check the inside of the bolt just ahead of the ejector area to make sure there isn't a rough spot that would create drag on the case as the ejector is trying to push the casing out of the recess in the bolt face. Perhaps your extractor is putting excessive pressure on the extractor rim and is pressing it onto the opposite side of the bolt.. If the groove in the extractor isn't deep enough, or if the extractor is putting too much pressure on the extractor rim to the opposite side of the bolt, it could be causing the issue.