Material Availability Problem

In some cases when a sales order is made for a material, the availability check shows the confirmed quantity but for a date in the future.

This is a regular problem around here since sometimes the deliveries dont show all the materials on the sales order.

If someone can tell why this happens and if this can be fix.

Like for example a material with stock that I check in MD04 and had no pending deliveries, the confirmation of the availability check of the delivery was set for tomorrow not right away.

Best Regards,

Carlos