Antonio,
This is rather bizarre. In your item 10, the material is transferring requirements into the MTS segment, but in your item 20, the material is transferring requirements into the MTO segment.
I believe someone has been 'fiddling' with configuration of either item categories, schedule line categories, or settings in the material master, during the time after item 10 was created but before item 20 was created.
Depending upon what was changed, and when it was changed, running program SDRQCR21 against this material might correct the item that does not match with the current config and master data settings. Or, easier, you should just reject this SA, and start with a new one.
Best Regards,
DB49