My marlin started to do that maybe even worst than yours, defenetly a head space thing. I sent it in to marlins Canadian service depot took a long time but I got a new bolt.
Scary thing was the gun was not new, this problem developed over time(1000-2000 rounds at least). I have no idea how that can happen. I have not had much of a chance to shoot it since I got it back it's actually a little stiff while feeding ammo now.