Duplicates move back to original object when changing frame

This is such a pain, it’s happened before and I can’t remember how I fixed it - there are a few objects that move to the same position as the ones i copied them from whenever I change the frame i am working on, any idea how to stop this happening?

I’m working in 2.5, I’ve deleted all the keyframes I can find and as far as I can tell there aren’t any curves. I’m just getting this from things I’ve read on the forum with similar problems, my actual blender knowledge is very little

any help is sincerely appreciated

Either those objects still have keyframes on them or they’re somehow constrained (via parenting or an actual constraint) to another object that has keyframes.