I guess a corkscrewing pellet every once in awhile is not an uncommon thing. Ted had a couple on his last video with that less than MOA session at 100 yards.
You have a very fine gun, a peace of art, It should also shoot like it, Please send it to Earnest before any grinding tools come out, With a Earnest tune it will just up the value of the gun, Win win thing. Please put the sand paper down and the drimel tool , Something's you can not fix, Mike