Is a slightly-deformed clay pipe a concern?
I suspect that's just an artifact of looking at two round pipes joined. The city sewer is not square, so the house pipe is longer on the bottom and the top than it is in the middle, to fit to the hole in the city line. It's probably also not at a 90 degree angle, so there may be some left/right difference as well.

Probably the most common thing you can quickly look at (from the outside) to get an idea is the joints on a bicycle frame.

It's called a "fishmouth" becasue the prepared end of the pipe looks a bit like one. You are looking at that from inside. Remarkably clean line, by the way.