I have changed your post’s title, though i’m not sure i quite understood your question. But this is not enough to put “Ask” in the title. You have to describe your issue at least with 3-4 words.
Now, can you describe again what is your issue? Communication in xmpp/jabber network is always going client-server-client way. So it is naturally that then Spark sends a message to another Spark user it goes to Openfir first and then Openfire transfers it to that another Spark user. so in that case you should see traffic coming from Openfire to Spark client. With file transfers it is usually client-client scenario and Openfire shouldn’t be involved, unless there are some obstacle for file transfers (firewall, NAT) and Openfire is set to behave as a proxy. Then file transfers would also go thrugh Openfire.
Other than messages there plenty of other data Spark may be getting from Openfire. E.g. presence updates about other clients (online, away, busy, etc.). Roster updates (who is on the contacts group and in what group). Group chat (all group chat history is managed and stored on Openfire server).