This is an Apple bug. Send a bug report to them. If they get enough bug reports they may do something about it, although currently they don't plan to fix it. (See the May 21 entry in this blog for some comments about this problem.) This problem was observed using Apple Preview to write meta information, but if it also affects Aperture, it may affect all Apple products. Wow. This is big.

Here is the HtmlDump of your image. The problem is that Apple has deleted an entry from IFD0 and not properly adjusted the count of items in the IFD. In your image, the "IFD0 entries" count is 8, but in fact there are only 7 entries. This results in an 8th entry that is invalid (yellow/brown in the HtmlDump), and an invalid "next IFD" pointer (red).

This is a serious problem which will result in the loss of information in your image. And it turns out that the deleted entry is YCbCrPositioning, which is a mandatory tag according to the EXIF specification, so Apple shouldn't even be deleting this in the first place.

- Phil