Oracle Message ORA-04099 - trigger string is valid but not stored in compiled form

ERRORtrigger string is valid but not stored in compiled form
CAUSEA trigger was attempted to be retrieved for execution and was found to be valid, but not stored. This may mean the an upgrade was done improperly from a non-stored trigger release.
ACTIONAlter compile the trigger to create the trigger in stored form. Also, you may want to review that a proper upgrade was done.