Invalid number of related objects.
This error is currently associated with Sketch3d objects. As of now, we know that a Sketch3d object cannot be standalone. It must have a relation to some other entity (other than its internal entities). However, due to incorrect propagations in the data model, the Sketch3d entity may remain in the data model, whereas, the outer object may get deleted. The script detects this error and logs it with the above error message.
Data model propagation errors in an earlier version.
The Sketch object becomes orphaned and remains in the database.
What You Should Do
Object needs to be removed. The removal procedure needs to be determined.