XMPP bot on App Engine

XMPP bot on App Engine

I have an old, long running chatbot application that for the last month
has stopped sending an initial dialog in the even that a chat message is
opened and directed to the chatbot.
Detail: You're in your Gmail (or Gtalk) and click on my chatbot contact to
start a chat conversation. In the past I would get the chat window with a
preemptive response from the chatbot. e.g. "This is a chatbot. Start
talking to me!".
Now I only see an empty window without any preemptive text.
The server logic is designed to acknowledge the presence request from any
subscribed client within my domain. This allowed my chatbot's status and
preemptive message to be sent simultaneously.
What I am wondering is if either of these behaviors are abnormal. Where
can I start looking to find the root problem? I have registered an XMPP
error handler on GAE but no errors have been captured. Wireshark captures
show nothing unusual on the sending end.
I've been reading these and similar docs for awhile now....
http://xmpp.org/rfcs/rfc6120.html#stanzas-semantics-presence
Any thoughts?