It annoys me that canon added a non broiled wide strap to the t6i. For the money I spent I feel like i should have gotten a wide strap like the t5i, t6, t4i...
This happened to me last month. I was cleaning the camera with a brush when I put the lens back and looked through the viewfinder I saw a string from the brush. I took the lens out again blew air with my rocket air and cleared it out.