Extract from email received back from IV - seems early versions of their upload software did do this but new versions do not.  It seems to have affected over 200 of my jpg's which I have had to "clean"

"Thank you for your inquiry. An initial edition of our Image Manager batch
uploading software has been using IPTC Instruction field in order to store
the information you enter in the mentioned Image Manager software. This
usage complies with the general designation of the IPTC Instructions field
as per IPTC specifications. The only purpose of this storage has been to
make Image Manager submit the image information that you enter with the
image itself, thus speeding up the submission process and avoiding
incomplete submissions.

But despite the idea looked good in the beginning, we received a number of
messages from our users who expressed their concerns regarding this policy,
and in reaction to that, Image Manager has been modified to keep the image
data inside a separate data file. Since that update, Image Manager is not
touching IPTC Instructions field. If you would like to update your version
to the latest release, please feel free to download the new installation
package:

http://www.imagevortex.com/downloads/image_manager/imsetup.exe

You do not need to uninstall a previous version before installing this one,
it will update automatically (please just make sure to close Image Manager
before starting the installation).

We sincerely apologize for any inconvenience caused by storing user-entered
information in the IPTC fields. Should you have any further questions,
please don't hesitate to let us know. "

So that's alright then    Not