That was my first thought also. Bit of trash in the chamber at the shoulder /neck junction.1. Could be a speck of dirt or carbon in your chamber. Cleaning it should clear that up. If it's after sizing, could be too much lube as others have said. Either way, it won't be a problem to load and shoot.
2. Pretty standard for bushing dies and isn't an issue. The Short Action Customs modular sizing dies don't leave that unsized portion because the bushing sizes the entire neck along with bumping the shoulder back.