Saved PSD files show up as small thumbnails oinly in Bridge

Ive been working on some photos in ACR/CS2 and a strange thing happened. After working on raw files I save them in a separate working folder as psd files. Suddenly, for no apparent reason, my PSD files are showing up in Bridge as tiny thumbnails. This just started happening in the middle of working on a folder of raw files. The first few were fine and then the saved files began showing up as thumbnails.

Moving the slider to make them bigger doesnt do anything. I can make all the files smaller by moving the slider to the left, but moving to the right only makes the files thumbnail size. Very weird. This problem seems limited to Bridge. In PS they look fine. Ive even checked their file size and that looks fine. Ive closed and reopened Bridge, but that had no affect.

I cleared ACR preferences and purged the folder; that brought back some files but then others became small. Also when working on new files, the first few were again OK and then again files became thumbnail size in Bridge. I can open the files, save them to another folder and then copy them to the original folder, over writing the old, thumbnail size folder. I suspect all this has to do with cache and some setting, but I can't figure out the random nature of all this.