Ran into a curious problem were a user on GW 8 PO complained that their
email messages to their BlackBerry were being delayed 15 minutes.

Tracked the problem down to event notifications in the POA, at sometime the
POA stopped updating the notification events and the BES SOAP connection
didn't see any new events for that user so it would go into a fall back mode
to check for new items every 15 minutes.

Stumbled across this TID from RIM explaining the SOAP SLAP notification

How I fixed it? Went to the POA web monitor interface, then to
"Configuration" then selected "Event Configuration List", found the user,
selected "Add to Notification List" and clicked the submit button. After
that, no more 15 minute delays and BES email to this user was instant.