Short version, chamber looks to be reamed without a floating reamer holder, has the chamber slightly oblong due to such, and then instead of CNC tooling to created the chamber beveled chamfer'g entrance, straight cutter used to single edge cut it at a fixed angle isntead.
Or, someone went in with a chamfer tool by hand, after they received the barrel isntead.
What is should look like isntead,
Do depending on how out of round chamber is in regards to side wall to side wall concentric to begin with, and how deep the chamfer straight entrance cut was made, barrel may be savable, but if your not gear up with lathe and tools to correctly do the work, them call the barrel toasted, since can pick up another barrel for what you way pay a smith to fix the barrel isntead.
Hence to fix, barrel extension needs to be removed, both breach face and barrel extension shoulder set back for one more winds of the barrel extension (.0357"), barrel re-chambered the .0357", chamfer entrance cut correctly this time to clean it up, barrel extension reset so it pin is TDC of gas port and torqued to 175ftlbs.
But, this is going to move the end of gas tube the .0357" deeper in to the gas block, as well as move the front barrel clip for hand guard the same distance as well towards the delta ring; a real PITA to get the delta ring compressed that extra distance back to reinstall the hand guard.
So normal location that gas tube should stop,
And depending on the carrier key in play, with end of the tube now .0357" pushed back in the receiver, could cause some problems as well.