Problem Statement

There is an anomaly with the vendor calendar in Dynamics 365 Finance & Operations when used with subcontracted production orders scheduled Backward from delivery date.

After activating the vendor (supplier) calendar, the system calculates inconsistent requested and delivery dates between:

• Purchase order header
• Purchase order line

Specifically, when a subcontracted production order is scheduled backward from the delivery date, the purchase order line delivery date no longer matches the purchase order header delivery date.

This behavior creates incorrect and misleading supply dates.

Current Behavior

• Vendor calendar is activated and assigned correctly.
• Production order is created for a subcontracted item.
• Scheduling direction is set to Backward from delivery date.
• Master planning or production scheduling generates a planned supplier order.
• Planned order is firmed into a purchase order.

Result:

• The purchase order line delivery date differs from the purchase order header delivery date.
• Requested entry dates in the planned supplier order do not align with vendor calendar working days.
• Vendor calendar appears to be partially ignored or inconsistently applied during backward scheduling.

Expected Behavior

• Vendor calendar should be consistently respected during backward scheduling.
• Purchase order header and line delivery dates must always match.
• Requested and confirmed dates should:
• Respect vendor working days
• Be aligned across planned orders, purchase orders, and production orders
• Scheduling logic should behave the same regardless of scheduling direction (forward or backward).