moby: Bad permissions on a trusted container, but correct permissions locally

I’ve hit a bug where the Unix permissions are wrongly set when the image is built automatically (trusted build) but when I run the build locally (using the same Dockerfile) everything is fine.

How to reproduce:

$ docker --version
Docker version 0.11.1, build fb99f99
$ docker run -it tinyerp/sandbox-postgresql
root@4871d1b57a8e:/# service postgresql start
 * Starting PostgreSQL 9.3 database server                                                                                           [ OK ] 
root@4871d1b57a8e:/# sudo -u postgres createdb testdb
createdb: database creation failed: ERROR:  could not create directory "base/16385": Permission denied
root@4871d1b57a8e:/# ls -l /var/lib/postgresql/9.3/main/
total 64
-rw------- 1 postgres postgres    4 May 18 16:16 PG_VERSION
drwxr-xr-x 8 root     root     4096 May 18 16:20 base
drwx------ 2 postgres postgres 4096 May 18 16:20 global
drwx------ 2 postgres postgres 4096 May 18 16:20 pg_clog
drwxr-xr-x 6 root     root     4096 May 18 16:20 pg_multixact
drwx------ 2 postgres postgres 4096 May 18 16:20 pg_notify
drwx------ 2 postgres postgres 4096 May 18 16:16 pg_serial
drwx------ 2 postgres postgres 4096 May 18 16:16 pg_snapshots
drwx------ 2 postgres postgres 4096 May 18 16:20 pg_stat
drwx------ 2 postgres postgres 4096 May 18 16:26 pg_stat_tmp
drwx------ 2 postgres postgres 4096 May 18 16:20 pg_subtrans
drwx------ 2 postgres postgres 4096 May 18 16:16 pg_tblspc
drwx------ 2 postgres postgres 4096 May 18 16:16 pg_twophase
drwx------ 3 postgres postgres 4096 May 18 16:20 pg_xlog
-rw------- 1 postgres postgres  133 May 18 16:20 postmaster.opts
-rw------- 1 postgres postgres   98 May 18 16:20 postmaster.pid
root@4871d1b57a8e:/# 

The directories base and pg_multixact are wrongly owned by root when they should be owned by postgres.

This is the Dockerfile published (https://index.docker.io/u/tinyerp/sandbox-postgresql/):

# DOCKER-VERSION 0.11.1
FROM ubuntu:14.04

RUN mv /usr/bin/ischroot /usr/bin/chroot.orig \
 && ln -s /bin/true /usr/bin/ischroot \
 && export DEBIAN_FRONTEND=noninteractive LANG && apt-get update \
 && apt-get install -y --no-install-recommends language-pack-en \
 && update-locale LANG=en_US.UTF-8 && . /etc/default/locale \
 && apt-get install -y postgresql-9.3

RUN pg_ctlcluster 9.3 main start && pg_ctlcluster 9.3 main stop

CMD ["/bin/bash", "--login"]

The last RUN pg_ctlcluster instruction starts and stops the PostgreSQL server in order to create a DB user. (I removed the createuser -d openerp while troubleshooting the issue).

I’m puzzled why it builds without this error locally, but the image is built wrong on the public registry.