Yes, it does. A friend received tons of it from her mother in law and it was probably 25 years old. It all but fell apart. Her m in l lived in Hawaii so I don't know if the climate had something to do with it. Doubtful.
I agree with the other ladies in that I would buy all new. I've worked on one project for several years off and on and when I ran out of one color ( can't recall the number right now, sort of a light mint green) it was a totally different hue. Luckily it wasn't noticeable because of the way the pattern was laid out. From that experience forward, I always make sure that I have enough to complete a project when using from my stash.
I'm glad that you asked that question, I need to check my stash and possibly get rid of old "stuff".
Floss is relatively inexpensive and it would be a shame to invest so much time and money just to realize that there is a problem.