Definitely chipped extractor.
With the bolt removed, will a cartridge slide in and back out of the chamber without effort?
I had an extractor chip on a 1100 shotgun and the chip evidently entered the chamber and made a tiny ding in the chamber. After replacing the extractor a shell would slide in easy but hang.
My gunsmith had to remove the tiny ding in the edge of the chamber to correct the shell hanging.
I will check. Visually the chamber looks fine.