Hello Antonio Martinez,
AS you told details try to understand following , System creates reservation against production order for component & when you issue those component against production order by choosing "TO ORDER" option material issued against reservation for that particular production order. Hence system check reservation quantity for that material with reference to storage location & plant. If reservation not found for another plant system shows warning message. These material movements were called planned material movement.
In second scenario if you issue material without choosing "TO ORDER" system consider material issue except reservation for that material. Such type of transaction were carried out for adjusting inventory of material at the month end which is not standard practice. For your clarification check reservation created for material & material withdrawal against same reservation in both case. No reservation quantity reduced in second scenario.
Conclusion:- If you issue material by choosing "TO ORDER" system restrict wrong material issue . But if you issue material without choosing "TO ORDER" system will not restrict you for material issue. (Planned movement were restricted by system & unplanned movement allowed.)
Solution:- Aware your to follow standard practice by choosing "TO ORDER" for material issue against production order.
Hope this will clarify your doubt & issue will resolve. Check & revert.
Regards,
Shyam