Currently, prims owned by the script owner aren't able to be returned as per the wiki:

"As a security measure, parcel owner, estate owner, and estate managers can not have their objects returned by this method, except when the object returns itself."

...which is understandable for user-rezzed content.

Please update llReturnObjectsByID() with a check to allow return of self-rezzed objects.

These are objects rezzed by the same object calling llReturnObjectsByID().

Whenever I have a massive amount of content that I wish to update in an automated fashion, I can't complete the process without tedious, repetitive, manual intervention come time to return each object to my inventory.

This update would allow the process to be completely automated.