Late in Oct. Google Adwords help forum noted problems with Quality Scores to which Google claimed "This issue was limited to reporting of Quality Score, and the fix should be live for all within the next 24 hours. For those keywords with a status of Low search volume, the fix should be live within the next few days," reported AdWordsPMAdam, a Google employee.
But the problems is appearing again "as the help forum suggests the 'bug' wasn't fully fixed and some ads were showing very low QS and even notices that bids were too low to appear on the front page."
A "advertiser based in the UK tells, The Register that as his quality score has dropped, his cost per click has jumped from about £0.90 to £1.40 on one campaign."
intelliAd Media GmbH has seen major "rise of the keywords given a Quality Score of 5 or lower from 20 % to just under 70 % over the last few weeks. This's remarkable because the Quality Score is normally only subject to minimal fluctuation."
"We're seeing customers, where even their own brand keywords receive low scores and where the companies are experiencing major upsets as a result. However, a further investigation also showed that you cannot assume that click prices are rising across the board in this scenario," says Mischa R