Not in the thumbnails thoughI migrated to Aperture from iphoto recently. I had no problem with the same photos ever on iPhoto. Still when I use Loupe it shows the correct colours in the same areas.
iMac 27 i5, Mac OS X (10.6.4)
This indicates that you have highlights clipping turned on. You can turn it on and off by using shift-option-H.
Red is the highlights clipping warning overlay; Blue is the darks clipping warning overlay. "View➞Highlight Hot & Cold Areas" toggles the warnings on/off.
See here in the User Manual:
Showing Hot and Cold Areas in Your Images
If you use these frequently, I suggest assigning the command to a single key shortcut. I use "s".
Aperture shows strange reds and colurs in my photos.
