BUG #13916: Only the install user can be defined in the new cluster

The following bug has been logged on the website:

Bug reference:      13916
Logged by:          reiner peterke
Email address:      reiner.peterke@splendiddata.com
PostgreSQL version: 9.5.0
Operating system:   centos 7.0.1406
Description:

This appears buggy to me or at least inconsistent.

using pg_upgrade to upgrade from 9.4.5 to 9.5.0

the upgrade runs then at the end prints.
Only the install user can be defined in the new cluster.
Failure, exiting

But when i look in the 9.5 cluster everything appears to be working with all
users.

I don't understand the error message especially since it appears to have
succeeded in the upgrade.

Am i missing something?