delivery completed indicator

Hello,

I'm facing an issue related to the delivery completed indicator in P.O.:

I've created some open purchase orders with quantities 100 TO. On the delivery tab of the P.O. , the "unlimited indicator" is marked automatically. When I create a first good receipt via MIGO with quantity 65 TO, I select the "Do not set" option of del. completed indicator on Purchase Order Data tab.

When I create a second good receipt with quantity 120 TO, I still select the "Do not set" option of del. completed indicator on Purchase Order Data tab.

Finally, when I want to create a third GR with quantity 85 TO, SAP system refuses the transaction. The error message is : "Document 4500509580 does not contain any selectable items". However, the delivery completed indicator is not marked on delivery tab of the PO ???

I thought that the unlimited indicator marked on the delivery tab of a open PO means you can create GR as many times as you want.

Thanks and best regards,

Lyd