So after the Google system bug that caused huge increases in minimum cpc that many thought (and I reported yesterday) was down to the latest Google quality score update, was apparently caused by a routine infrastructure update. The Inside Adwords blog explains -

Last Friday, during a routine infrastructure update, we experienced a technical issue that significantly increased the minimum bids for some keywords. Because the maximum CPC for these keywords was not changed, a number of impacted keywords became inactive for search, resulting in fewer leads for some advertisers. This technical issue was completely unrelated to the Quality Score updates that we have planned for later this week.

These issues was fixed fairly quickly, by Saturday morning for most of the keywords. But lets not forget, just because the maximum cpc was not effected, the minimum cpc was raised so there could well be many advertisers that were automatically forced to pay a higher price with the minimum cpc increase.

The message from Google on this is -

Once we have completed our analysis of the impact, we’ll automatically issue credits to advertisers who overpaid due to this issue. As soon as these credits have been applied, we’ll email the affected advertisers to let them know.

Take a close look at the price you paid over this period.