Riding any distance with an underinflated tire can cause this to happen. Narrow tires need a lot of pressure, and unless you are checking with a gauge you might not even realize you are underinflated.

I also have seen defective tires where the sidewalls where it meets the bead cannot handle its rated pressure long term, but that is rare, and was generally only one manufacturer that you would most commonly get it (Specialized), in my experience.