Monitoring archive: delivering too many messages?

Folks;

using openfire 3.10.2 with monitoring plugin in order to achieve server-sided chat archiving, I just stumbled across a strange behaviour all along with using the Conversations XMPP client on Android: Essentially, the app tries to fetch messages from the server-sided archive for most (all?) of my contacts. Conversation tries to fetch messages in a given timeframe (in example, two days ago) - and then keeps processing a whole load of messages seen before because openfire does obviously return a bunch of messages that are way older than this given timeframe. Arguably it’s even older than the 25 days I configured for “retrievable messages” in openfire configuration.

Is this an intended behaviour? Who’s “wrong” here - the app or the server? What to do about it to fix it?

TIA and all the best,

Kristian