Well.. Let's see. Fires, cycles, and won't fire the next round which got chambered (ejected live round), manually cycled and then fires.
Is it possible that the return spring isn't closing the bolt fully on the new round? If you take the rifle out to the "field" and try getting it to repeat this issue - fire it once, LOOK at the action - is it closed completely?
Is it possible that the barrel isn't lined up completely right so the extractor isn't going into it's slot under normal spring pressure, but does when you manually close it.
Another "test" fire the rifle, push the bolt handle forward -does the bolt move forward or is the action fully closed? If the bolt moves forward, it's not completely closed. Check the barrel alignment to ensure the ejector goes where it's supposed to..
My thoughts, anyway. A "field strip" may or may not fix this if you don't RnR the barrel.