That is an awesome feature however, they are still blurry. Is there a way to clear them up? I can get 2 of the photos from those sessions to load and clear up but the rest of them are blurred.
No, I don't think so that there's any other way to fetch the missing images out from Lightroom.
That is the catch when pulling things out of the cache. The cache only contains the most recently used files, and only the format of the files that was recently needed. Because you probably did not get around to viewing the hi-res version of every image in LR, LR did not create a hi-res version in the cache of all the files.