without making code changes, you can't share items between 2 repository modules, each repository module (identified by the unique Module ID assigned to it when you placed it on a page)  has it's own set of data items.

Using the 'copy' funciton to place a copy of the module on a different page does not create a 'new' module, changing the data in one instance will affect the other instance as well .. in effect it's the same module, just on two pages, which is why the Dashboard module seems to be getting confused.

To accomplish what you want to do, you would have to change the stored procedures in the database to return data items regardless of module id, so all repository modules would share the same data (ie: remove ModuleID from the WHERE clause). Then you could place 2 separate repository modules on 2 different pages, each module would have a unique ID and you would be able to change the settings for each one independently.  The only downside is that if you do that, then ALL repository modules on all of your portals within that dotnetnuke instance would share all of the same data items, however if these are the only two instances of the repository module that you plan to use, then that would most likely work