Only on environments which are upgraded to 10.32 there's an issue with updating the datamodel and the following error message is received:
Caused by: com.hp.ucmdb.api.ExecutionException: appilog.framework.shared.manage.impl.MamResponseException: [ErrorCode  Action is not allowed, can't add STATIC_ATTRIBUTE qualifier to an attribute] com.mercury.topaz.cmdb.shared.base.CmdbException: [ErrorCode  Action is not allowed, can't add STATIC_ATTRIBUTE qualifier to an attribute]
Code problem fixed in 10.33, however it cannot be backported due to the number of changes in the GUI & all the jars.
Workaround / Fix
The only available work aroiund to apply changes on the data model is through the JMX:
When you navigate to JMX Search : listResourceTypes > CM_CLASS > edit the desired class: > perform the desired changes on the class > Save resource @ the bottom of the page.
Then restart the UCMDB server service