Wow, I had a list of keywords that were at 8/10 minimum with one of them being a 10/10 for a week just fine, $.12 CPC. Just randomly dropped to a 4/10 and 6/10 range and raised to $.40 CPC. What the hell, I don't get how google adwords works at all...
Sounds like their adwords bot may have re-allocated your landing pages and keywords etc a new QS. If you CTR is low, your quality score can drop dramatically, CTR a huge factor in the overall quality score - try tightening up those ad groups and experimenting with catchier ad text.