YOU_CANNOT_ADD_AN_ITEM_AND_PURCHASE_ORDER_COMBINATION_THAT_DOES_NOT_EXIST_TO_A_VENDOR_BILL You cannot add an item and purchase order combination that does not exist to a Vendor Bill.

AI generated answer (using internal Slack threads):

Based on the conversations, it seems that you cannot combine multiple purchase orders from different vendors into a single bill. This is likely due to the potential ambiguity in identifying which vendor to use for the bill. When transforming a purchase order into a vendor bill, all the items and quantities are taken into account. This is because you could pay for the whole purchase order before it is fully received. If you want to bill only the items that are received, you would need to transform the purchase order, then query up the item receipt data in order to remove/change the lines on the vendor bill. However, if you disable the 'Bill in Advance of Receipt' preference, this might solve the issue. Please note that these are general observations and might not apply to all scenarios. Custom logic might be needed to handle specific cases. ****** Disclaimer: This response was generated by an artificial intelligence assistant based on previous conversations from multiple Slack channels, and may contain inaccuracies or mistakes. ******