Yeah - what ssprengel said...
To reiterate, if problem was due to Canon's compression algorithm, then the file would never have been interpretable - not even once. Note: Lr does not write to CR2 (or CRW) files, it only reads them, so if it was good once, then bad, it went bad. Again: the situation is complicated by the fact that some software will just display a preview, or even if displaying a raw, handle bad bytes differently...
Allan may have a point - that the compression algorithm changes the symptom in Lightroom when only one byte (or only a few bytes...) goes bad, but that can only explain why there seems to be a higher incident of corruption in Canon raws (i.e. one bad byte can cause streaks instead of unnoticed dots) - I'm not convinced that's true, but I can't claim it's not...
So, once again, the problem is not Canon software, nor Lightroom, but your hardware...
If that turns out not to be true, I'm sure all of us claiming it was true, will be happy to eat our hats, and some crow, maybe a little humble pie... (ok, maybe not happy, but you get my point, right?), but so far we've never had to...
Rob