There's currently a System Alert on OCLC's site for this issue
(http://www.oclc.org/support/systemalerts/):

Alert Topic: Local Holdings 007 field expansion problem
Alert Status: Condition reported
Affected Services: Connexion browser, Local Holdings Maintenance
Alert Created: 01/16/2007 3:07:39 PM ET
Last Updated: 01/16/2007 3:07:39 PM ET

Description: There is a problem with the values in the 007 (Physical
Format) field in Local Holdings records. This problem impacts both
existing Local Holdings records and LH workforms. If a library accepts
the values in the existing LH record in the workform and does not expand
the 007 field, then the record/workform can be validated and updated.
However, if the library expands the field, the values become mixed up
and the record cannot be validated or updated.

Additional Notes: Staff are continuing to investigate this problem and
working toward a resolution.

Keri Cascio
Librarian/Trainer
Missouri Library Network Corporation
keri@mlnc.org
1-800-969-6562 x813
http://www.mlnc.org