Files disappear when moving boards

have 4 boards utilized in one “workflow”
Board 1 being our “database” of jobs we attach all supporting documentation and information there.
create an automation that we can click to move to board 2->3->4 to finish billing cycle
the files we attached on board 1 are showing there but when duplicated and moved to board 2,3,4 the files are lost… (also creates a (copy) in board 1 also annoying)
how can I keep files attached

To confirm - are you ‘creating a copy’ and then moving the copy to the next board?

We used to do this and now use ‘Same Item Multiple Boards’ app instead.