Here's another where the message didn't show in my Spark window, but it opened and flashed.
<iq to="gretchen@OpenfireServer/Spark 2.6.3" id="jy7qe-24829" type="get" from="glenda@OpenfireServer/Spark 2.6.3"><query xmlns="jabber:iq:last"/></iq>
<message to="gretchen@OpenfireServer" id="jy7qe-24831" type="chat" from="glenda@OpenfireServer/Spark 2.6.3"><thread>Ydl73u</thread><composing xmlns="http://jabber.org/protocol/chatstates"/></message>
<presence id="n5D6o-1128" from="rob@OpenfireServer/Spark 2.6.3" to="gretchen@OpenfireServer"><status>Away</status><priority>0</priority><show>a way</show><c xmlns="http://jabber.org/protocol/caps" hash="sha-1" node="http://www.igniterealtime.org/projects/smack" ver="TJuVIXqTCVfJSthaPu4MtTbaf9A="/></presence>
<message to="gretchen@OpenfireServer" id="jy7qe-24833" type="chat" from="glenda@OpenfireServer/Spark 2.6.3"><thread>Ydl73u</thread><composing xmlns="http://jabber.org/protocol/chatstates"/></message>
<message to="gretchen@OpenfireServer" id="jy7qe-24834" type="chat" from="glenda@OpenfireServer/Spark 2.6.3"><thread>Ydl73u</thread><composing xmlns="http://jabber.org/protocol/chatstates"/></message>
<message to="gretchen@OpenfireServer" id="jy7qe-24835" type="chat" from="glenda@OpenfireServer/Spark 2.6.3"><thread>Ydl73u</thread><paused xmlns="http://jabber.org/protocol/chatstates"/></message>
<message to="gretchen@OpenfireServer" id="jy7qe-24836" type="chat" from="glenda@OpenfireServer/Spark 2.6.3"><thread>Ydl73u</thread><composing xmlns="http://jabber.org/protocol/chatstates"/></message>
<message to="gretchen@OpenfireServer" id="jy7qe-24837" type="chat" from="glenda@OpenfireServer/Spark 2.6.3"><thread>Ydl73u</thread><composing xmlns="http://jabber.org/protocol/chatstates"/></message>
<message to="gretchen@OpenfireServer" id="jy7qe-24838" type="chat" from="glenda@OpenfireServer/Spark 2.6.3"><thread>Ydl73u</thread><composing xmlns="http://jabber.org/protocol/chatstates"/></message>
<message to="gretchen@OpenfireServer" id="jy7qe-24839" type="chat" from="glenda@OpenfireServer/Spark 2.6.3"><thread>Ydl73u</thread><composing xmlns="http://jabber.org/protocol/chatstates"/></message>
<message to="gretchen@OpenfireServer" id="jy7qe-24840" type="chat" from="glenda@OpenfireServer/Spark 2.6.3"><thread>Ydl73u</thread><composing xmlns="http://jabber.org/protocol/chatstates"/></message>
<message to="gretchen@OpenfireServer" id="jy7qe-24841" type="chat" from="glenda@OpenfireServer/Spark 2.6.3"><thread>Ydl73u</thread><composing xmlns="http://jabber.org/protocol/chatstates"/></message>
<message to="gretchen@OpenfireServer" id="jy7qe-24842" type="chat" from="glenda@OpenfireServer/Spark 2.6.3"><thread>Ydl73u</thread><paused xmlns="http://jabber.org/protocol/chatstates"/></message>
<message to="gretchen@OpenfireServer" id="jy7qe-24843" type="chat" from="glenda@OpenfireServer/Spark 2.6.3"><thread>Ydl73u</thread><composing xmlns="http://jabber.org/protocol/chatstates"/></message>
<message to="gretchen@OpenfireServer" id="jy7qe-24844" type="chat" from="glenda@OpenfireServer/Spark 2.6.3"><thread>Ydl73u</thread><composing xmlns="http://jabber.org/protocol/chatstates"/></message>
<message to="gretchen@OpenfireServer" id="jy7qe-24845" type="chat" from="glenda@OpenfireServer/Spark 2.6.3"><body>Hi Gretchen, i am working at home, i laserfiche kicked me off yesterday and now today again. Do you know if we are having problems?</body><thread>Ydl73u</thread><x xmlns="jabber:x:event"><offline/><composing/></x><active xmlns="http://jabber.org/protocol/chatstates"/></message>
<presence id="qXk1H-10" from="crystal@OpenfireServer/Spark 2.6.3" to="gretchen@OpenfireServer"><status>Online</status><priority>1</priority><c xmlns="http://jabber.org/protocol/caps" hash="sha-1" node="http://www.igniterealtime.org/projects/smack" ver="TJuVIXqTCVfJSthaPu4MtTbaf9A="/></presence>
<message to="gretchen@OpenfireServer" id="jy7qe-24848" type="chat" from="glenda@OpenfireServer/Spark 2.6.3"><thread>Ydl73u</thread><paused xmlns="http://jabber.org/protocol/chatstates"/></message>