when switching on the parameter "Coverage Plan by Dimension" on "yes" one of the tracking dimensions the system always will require a value for the dimension. Empty is also considered as a value.

The behavior we no see shows that when for example a batch is filled in on the demand (Sales Order) it will be transferred to the supply (purchase order) which is what we want.
However when on the demand the batch is left empty and the masterplan is used it will create als a supply with batch empty. This not a problem however somewhere in the flow the batch number will filled (depending on parameters when this will be done) when on the supply the batch number is filled, and the MRP is run again it will create a new supply with empty batch number even if there is a marking with the supply which has been created before. This is an unwanted situation as it will result in a new supply order (purchase) also with a marking to the demand. In this way there are two orders marked against the demand and we get to much supply.
Empty batch should be considered as "all batches allowed" and not in multiple MRP lines when the marked supply finally gets a batchnumber