thanks in advance for any ideas.
I'd be looking at what hosts do you have, and whats running in them, which
adapters are running in which host, and the sequence of how you bring them
back up.
If you bring up the receive host before your processing host you'll get
failures, as the subscriber is not there it's not running. Look at the
sequence of how you bring it all back up again.
Worst case you can extract these messages and see what they are, putting a
port to subscibe to these types of messages in the filter, before they fail,
will give more detail on exactly why this is occuring.