BUG #13809: Reassign owned throws error

The following bug has been logged on the website:

Bug reference:      13809
Logged by:          Alexander Ashurkov
Email address:      alexander.ashurkov@gmail.com
PostgreSQL version: 9.4.5
Operating system:   Linux 3.19.0-31-generic #36~14.04.1-Ubuntu SMP Thu
Description:

Hello,
when I execute "reassign owned by user to user_role" command (even with
'postgres' user) postgresql outputs this message:
"ERROR: unexpected classid 1418
SQL state: XX000"

My DB has postgresql FDW (it owned by 'postgres' user as it should be), one
foreign server (owned by 'user_role') and two user mappings for 'user' and
'user_role'.

'user' is member of 'user_role' ('GRANT user_role TO user').

Postgresql installed from "deb http://apt.postgresql.org/pub/repos/apt/
trusty-pgdg main" repo.

With version 9.4.4 it worked fine. Do I miss something or it is a bug?