Odd behavior with subscription to promoted property

Hello folks, got this head-scratcher of a behaviour.  A schema with a promoted property, xml files received from FTP server.  An orchestration subscribes to the receive port and the promoted property, and this works fine.  A send port group subscribes to the receive port and the promoted property and this correctly archives the raw message based on subscription, but the element that was the source of the promoted property is nulled in the archive.

the promoted property is

<WOLO2>SOURCE123</WOLO2>

After writing out the message archive the file remains intact except that now I have

<WOLO2/>

There is no mapping involved on the receive port or send port, and I know the subscriptions are working as both the orchestration is initiated and archives are routed corrected.

So I go and create a new send port and only subscribe to the receive port, and these is no issue with that archive, writes out <WOLO2>SOURCE123</WOLO2> for the same message.

it’s not the most impacting of problems, it only really affects me if I have to reprocess raw messages, and I can work around that.  It’s just confusing to me why it should be removed from the raw document by participating in the send port subscription.

Any thoughts out there or problem solving approaches to try?