Sam,
311 is Transfer posting storage location (one-step) in ECC. This means you are transferring material from storage location to another.
Are you creating reservation (MB21) for posting 311? Is this captured as demand in APO (example as sales order with some custom development or something else) and finally consumed against forecast? Are you working with MRP area i.e. is it active in your system?
Check above points and let us know.
Regards
Rahul