Elastic tensioner broke.
The elastic tensioner on the back of the cap was too tight. I was seeing how and if it was adjustable. The elastic pulled out of hat on one side. Looked as if the sewing machine only scored a couple stitches at the very end of the elastic strap - not enough to hold it securely. Not a big deal. I affixed the elastic back into the cap with a drop of Gorilla Glue.