We have a 2006 S60 AWD, owned about ten years. Three times in the past fifteen months or so it has done this disturbing thing where we are in cruise control at highway speed and need to brake for entering traffic or a slowdown ahead, and the brake pedal is hard as a rock, like there's no power assist. We've managed to slow the car enough each time to avoid an accident but it takes a lot of force and much more distance than it should. This has happened with two different people driving. If we turn cruise control off, the problem vanishes. I'm concerned that with how rare this is, it'll be hard to track down. Anyone heard of anything like this?

Thanks for any clues...