How are you duplicating the spooled files? It’s likely that whatever method you use, the overlay information is not copied with the rest of the attributes.
You would, I suspect, have to use a CHGSPLFA command to add the overlay information back into the copy (FRONTOVL parameter).
You may be able to automate this by using WRKSPLFA on the original spooled file (output to a file), then read that file and get the overlay information, and then apply it to the copy using CHGSPLFA. However, I have not checked whether the file output from WRKSPLFA actually would contain the overlay information (we don’t use overlays here).
will add this. I use page segments and overlays all the time. I have found. When you copy a spool file that has a overlay and restore it to another machine. You must have the overlay in the same library on the new machine or else when you print the form. You will not get the overlay. If you move it to a new output queue on the same machine. You must still have the library that had the original overlay in it. Available when you print it. I hope this helps.