Anyone else use DR strings? I've been using Pure Blues 10's for a while and although I really like the way they play and sound, I've come across some problems with the D string. For some reason I start to get little lines or grooves where the frets make contact with the string. Only happens on the D string. A few times the string started to unwind and chip away at these contact points. This happened just two weeks after changing strings, so it isn't just that they were old. I'm thinking of switching strings but other than the D string, I have no problems with them. Anyone else run into this problem? I've never had it happen with any other strings unless it was on a guitar I hadn't changed strings for a year+.