Sorry, I forgot to add that I have tried two different pairs of headphones.

I did take it apart and resoldered down the connector. I does seem more stable now (before I could get no audio when I twist the plug, now there is always some audio), but it still is intermittant/crackly. I don't know why resoldering make it better. I need to do some more running with it to see if I actually changed anything. I'll also get some contact cleaner and clean the jack to see if that helps.