In bug 974352 we made the warnings about XMLRPC retries go to the logs (the implementation we inherited from Kobo sends the message to stderr which is lost in daemons). However in Beaker 23.0, commit 429ca1d9effa7e000de2745846d1f6f8dcd5518e, bug 1309906 this regressed and retries are no longer logged.
http://gerrit.beaker-project.org/5291 configure logging in bkr client
http://gerrit.beaker-project.org/5292 consolidate retry_transport and retry_request_decorator
Beaker 24.0 has been released.