Demand Fulfilled late by one week in CTM Run

Hi SAP Guys

we have an issue in our CTM Run.Our Planning happens according week.we will run for horizon of 6 months.we are seeing issue in our run.for each week the demand is met within the same week but for particular week the demand is fulfilled late.we have checked every master data level by level,we see there is no with master data.we are seeing this for particular Material grp at a Particular Plant location.for other Material grp and plant the demand is fulfilled by the same week,for a particular week at particular plant @ one material grp the planned orders are not created.we are seeing this issue from past few weeks for every week when we run the CTM Run.

Thanks

SKM