Several target costs are zero for a production order after settled

Hi, my friends,

I have a very strange problem, hope you can clear my question:

I have done the varience calculation and settlement for a production order, but, in CO03->cost->analysis, several raw material are showing Target cost as zero and actual cost having some values and difference value is posting to resource-usage variences. In theory, all the target costs should have values after settled.

Why target cost is showing zero value in this case? Hope you can help me. thanks.