Chef Server 11.04 postgresql log errors

Any clues as to what is causing these in
/var/log/chef-server/postgresql? We have a pretty simple setup with 2
knifers
so far. The whole setup was pristine starting at 11.04, not
upgraded with baggage from 10.x, etc.

Repeating regularly (something’s trying to connect to PostgreSQL
as ‘chef’ which doesn’t exist?):

2013-08-28_12:12:03.01423 FATAL: role “chef” does not exist

More sporadic (it’s clear what this is, the question is why):

2013-08-23_16:17:36.91487 STATEMENT: INSERT INTO checksums(org_id,
checksum)
2013-08-23_16:17:36.91487 VALUES ($1, $2)
2013-08-23_16:17:36.91612 ERROR: duplicate key value violates unique
constraint "checksums_pkey"
2013-08-23_16:17:36.91613 DETAIL: Key (org_id,
checksum)=(00000000000000000000000000000000, e63ec30559419d397
22fa113306d4a22) already exists.