Requisition Import Group-By "Item" is not working properly

Hello Team,

We are using R12.2.5

In Purchasing >> Setp>>Organization>> Purchasing Options: We have setup Requisition Import Group-By field to "Item". So that when the users do Bulk receipt in Depot repair, the separate requisition should be created for each item. But when our 2 3 users are ding the bulk receipt at a time the requisition import program gets submitted and single requisition is getting created with multiple items with multiple buyers. But expected is, individual requisition should be created for each item.

But if the users are doing the receipt with some time one after other, then individual requisitions getting created for each item. Means its working as expected.