This would probably have to be reported to the Ubuntu kernel people? I have tried skimming over the changes between Ubuntu-7.0.0-28.28 and Ubuntu-7.0.0-28.28i2, but there was nothing obvious to me.
The problem was still present in 7.0.14-9 - just now rebooted my test machine into 7.0.14-11, but it usually takes a few hours or a day to run into a sample...