Hi,
What causes objects that are duplicated to not appear in a file when reopening it after having saved it?
What I think caused objects that were duplicated to move away from their original location, was an animation timeline add to another object.
I haven’t a clue how this could cause some objects to be moved after opening the file in the program. 
Duplicate object or duplicate linked ? From the same file or linked from another… ??
You may have to elaborate this to get a more suited answer.
The duplicate object was an original object, so once moved away from the original, on opening the program, the duplicate object is still in the same place as the original first one.
I did use a blend file to do my project as the desired effect I needed I couldn’t do myself, but I don’t see how that affect just creating an object, and then duplicate it and then move to somewhere nearby.
Editing animation or creating a new dopesheet, seemed to of caused the objects I duplicated to stay in one place or move to the center of the file. As that was the major change, I hadn’t touched any animation for the AI, even layer 0 or 1 for animation sequence, I seemed to understand that seems to make more than one animation work on an armature, as one user on here noted this, but I didn’t get what he was on about until I tried last weekend. 