Natural throws error code NAT0932 when the timestamp of the object code is changed. This happens by cataloging (CAT, STOW) the sourcecode. This also happens, if you replace the existing object code by an object code with a different timestamp (via SYSMAIN e.g.). This is my experience on Natural/mainframe.
So the following might happen: Someone wants to make modifications to the source/object code. First, the person copies the original source/object code to another library. Then it makes the modifications.
Afterwards the person copies / moves back the original Natural modules (including the directory information) into the library. Natural throws error NAT0932. But the timestamps of the directory information make you believe that no Natural modules have ever been changed.