SAP Note 13211 - Schedule lines not taken into account for GR

Symptom:

When a goods receipt occurs for a delivery schedule item, the
entire scheduled quantity (not yet delivered) is accepted. No
check against schedule line date is performed. A goods receipt
for an individual delivery schedule line is not possible unless
only one exists. This applies regardless of whether the delivery
schedule line was generated automatically or entered manually.

The same applies to a goods receipt for a purchase order item with
several schedule lines.

Cause and prerequisites

Schedule lines are always considered cumulatively. This means
that the total scheduled quantity up to the last scheduled date
should be delivered. Therefore, the system works as designed.

Solution
If you want to manage goods receipts separately for individual
delivery times, the release order function for contract items
is available.

Key word: MB01:sched.line