Item not located in subset when importing from the same subset
I am trying to import data from Module A to Module B, with both having the same two dimensions: "Market" and "Channel".
Both modules have a line item called "Product", formatted as a list "P3 Relevant Products" which is actually a subset of the list "P3 Products".
P3 and Market are Production Data and numbered lists, Channel is none of that.
The purpose is for the user to be able to import their selection from Module A, which is a few steps earlier than Module B, instead of selecting products manually if they prefer using the previous selection.
The two modules have exactly the same layout, format etc. Module B could very well be a copy of Module A using the copy module tool from Anaplan.
However when I import the data, I get the error "Item not located in P3 Relevant Products list" for all of them, despite the contents being obviously members of this list/subset because the format is the same.
I've seen some suggestions of workarounds using CODE or NAME in another line item and import this new line item but it would not work here as I need the users to select their data from the list P3 in both module and not write codes manually.
Does anyone know how to solve this issue ?