Does not always work correctly for all keywords in the list. Sometimes a few of the keywords are skipped and have the default max bid price set by adcenter. In other words, once you click that, verify that all your keyword bid prices have been updated in the list. Be careful, I realized this the hard way!
I have found the exact same problem but it only seems to have started in the last couple of days for me. It changed some of my mortgages keywords back to £24 when they should be £2 but i spotted it. Just be careful people and keep both your eyes peeled.