Before you take the bolt out you need to do the same thing several times slowly.... IMPORTANT. Use some dummy rounds, not live ammo!!
pull the charging handle slowly and every time w/o exception the round should catch into the extractor and then extracted and forced out as the tip reaches past the ejection port. Do it slowly and put your hand and you will feel the tip of the bullet tapping in your hand. In this case it will fall back into the chamber. Do it again and again slowly. And see if you can catch one where either:
A) The bullet comes w/o tension. sort of falling loose. B) The bullet disengages from the extractor. falls off before it reaches the opening.
I think you are looking at a case of either a sticky ejector/plunger(A) or a faulty extractor (B).
They both have springs that should have plenty of tension and move freely. See if you can catch the issue slowly as I described above.
It looks that your system is properly gassed so it has to be one of the above. Once you find the issue you need to take the bolt out and replace that part and spring unless the source is another like a metal shaving obstruction or something.