When it is misloading, how many rounds are in the mag box? Is it just the last one or just one in the box, or does it also do it when it is loaded full?

You could Open the rear of the feed lips a little to allow the case head to rise up a little further so that the bolt head catches the case head on closing the bolt.

Before you do that, you could try adding a thin(like 1/8-1/4”) shim or something in the bottom of the stocks mag well under the mag spring to give it a little more upward pressure. If that fixes it then it tells you that the spring is weak. And gets you Thru your hunt.
None of us can tell you 100% what the actual cause is without the gun in our hands, so you’re gonna have to try something to what you have or order new parts. But we can advise you on how to tweak what you have to either repair the issue or prove what is causing it.

You May need to do both?