found xmin from before relfrozenxid on pg_catalog.pg_authid

Getting some concerning errors in one of our databases that is on 9.5.11,
on autovacuum from template0 database pg_authid and pg_auth_members. I
only saw some notes on the list about this error related to materialized
views. FWIW, we did use pg_upgrade to upgrade this database from 9.4 to
9.5. Here is an example:

2018-03-19 12:08:33.946 CDT,,,14892,,5aafee91.3a2c,1,,2018-03-19 12:08:33
CDT,59/340951,0,ERROR,XX001,"found xmin 2906288382 from before relfrozenxid
740087784",,,,,"automatic vacuum of table
""template0.pg_catalog.pg_authid""",,,,""
2018-03-19 12:08:33.957 CDT,,,14892,,5aafee91.3a2c,2,,2018-03-19 12:08:33
CDT,59/340953,0,ERROR,XX001,"found xmin 2906288383 from before relfrozenxid
740087784",,,,,"automatic vacuum of table
""template0.pg_catalog.pg_auth_members""",,,,""

Any insight would be much appreciated.

Thanks,
Jeremy