MRP Not Create Lower Level Plan for Planned Work Order

Dear List,

I am on World 7.3 cum8 and try to run MRP for a parent-child BOM structure. For the parent, MRP generate planned work order for parent item successfully. For the child item, there is no message created to satisfy the parent item's planned work order's demand even though the planned work order is listed in the Supply/Demand inquiry screen. Please see the attachment for the detail.
Any thoughts and comments are very appreciated.

Hi , did you run P30601 prior to MRP ? This will rebuild lowlevel codes.

P30601 works its magic. After P30601, MRP message was correctly created. Thank you very much for the suggestion.