There is such a case when incorrect requirements are triggered from sales documents (sales order or delivery) may occur. By using transaction MD04, we can check what inconsistencies are occurred. These following errors absolutely can cause incorrect planning in production or procurement. This situation as per my experience is happened in make to stock scenario and you activate availability check and/or transfer requirements.
In my case, I found that in MD04 still contains a customer order number which is this order is already completed (full delivery). And after investigation, it is caused by my user exit in delivery that is deleted record but not clearly deleted, so in the table requirement list this records is still exist and appears that there are some stock need to be fulfill in requirement list.
Based on this sap notes: sapnote_0000025444 Recovery Sales & Delivery Documents
To make recovery of sales and delivery requirements, I used SDRQCR21. This is an executable program that run in SE38.
After, the report Recovery of Sales and Delivery Requirements appears, enter appropriate filter criteria that you want to analyze. Do not thick “Data transfer” if you just want to simulate. Let the selection rest by default, then click Execute.
The report, of recovery result in simulation mode then appear. After you check. Then the real correction can be processed.
Click back, and thick “Data transfer”, the correction into table requirements can be made. After that, check the result in MD04.