Aperture stretches or distorts some photos?

Hi guys!

New to the forums, new to Aperture! Had a quick search and found a kind of answer, but am hoping for something better!

Have recently made the transition from iPhoto to Aperture and am enjoying it very much. However am experiencing what seems to be a bug or glitch that I'm hoping there is a fix or work around that helps my workflow.

Some of the photos imported from my iPhoto seems to display incorrectly in Aperture. Typically they appear ok in the thumb, until I click them and then they often crop right into one corner of the photo, or stretch or squash to on one edge of the frame or just generally bug out. I can find no way of reverting this except (as suggested by one forum discussion) go back to iPhoto and reset the thumb. This works (phew!) so the photos are not lost, but it's a real pain and defeats the point in using Aperture to some extent as I have to keep reverting back to iPhoto. Seems mad that iPhoto handles the photos better than Aperture, no?

So does anyone know what causes this, is there a clean way to fix this or is there a swift work around that doesn't involve dipping in and out of programs? I have literally tens of thousands of photos so if there is a way to blanket fix the whole lot rather than manually fix each problem photo, that would be even better!!

Thanks in advance guys!

Chris