If in a dialog an asset was chosen and then deleted in the Asset App, the broken UUID does not get overwritten or deleted, even the dialog was saved with an empty value in the link field.

So it throws
2013-11-29 14:55:16,499 ERROR info.magnolia.dam.providers.jcr.JcrAssetProvider : Failed retrieve the asset node from dam workspace for the following node id 91e7267c-78e7-47f7-822b-dc9d8086b642:
javax.jcr.ItemNotFoundException: 91e7267c-78e7-47f7-822b-dc9d8086b642
at org.apache.jackrabbit.core.ItemManager.getItemData(ItemManager.java:384)
at org.apache.jackrabbit.core.ItemManager.getItem(ItemManager.java:328)
at org.apache.jackrabbit.core.ItemManager.getItem(ItemManager.java:622)
at org.apache.jackrabbit.core.SessionImpl.getNodeById(SessionImpl.java:536)
at org.apache.jackrabbit.core.SessionImpl.getNodeByIdentifier(SessionImpl.java:1102)
without a chance to remove this error, except adding a new image or delete the property in the JCR Browser.