Matching invoice to multiple shipments

Hi,

Version: 6.3.1

I have an standard invoice IV1 and 2 shipments S1,S2 in the system.  The invoice is eligible to be matched to both of these shipments S1 and S2. I am trying to auto-match it manually(as we typically do it once invoice is created in OTM) and it is throwing error with no shipments matched but invoice status says as MATCH_MULTIPLE_SHIPMENT_MATCH. Is this how the functionality works or is it a bug?

Then I tried using "find Valid Matches" and I am able to see the shipments S1 and S2 to be matched but I cannot match more than one shipment at a time and in this case I need to run the same action twice. We also have scenario when a single invoice is sent for 10 matching shipments. does the "Find Valid matches" matches an invoice to a single shipment ONLY at a time?