^ This. Heat is not so kind on binders. If it was on a hot cycle, that might have effected it some. I personally never had issues putting my binders through a cold wash and most were ok for the occasional (usually accidental) dryer cycle. One binder, however, did not survive the dryer of doom. Elastic thread poking out everywhere. Not a pretty sight. RIP. (It had gone through the dryer a couple times before that and was alright, fwiw.)
Only other thing I can think of is if it was sitting in a stretched position for a while, for example, wound around another piece of clothing. That can stretch things a bit too.