OS hosts not resolving after env update

Strange behavior was investigated during bug-fix process of the https://bugs.launchpad.net/mos/+bug/1364026 .
Short follow-up:
release 2014.1 (5.0) -> Upload and unpack tarball with fuel-5.1 release (build #499) -> update cluster to release 2014.1.1-5.0.2

Result:
...
[root@nailgun ~]# fuel node
id | status | name | cluster | ip | mac | roles | pending_roles | online
---|----------|---------------------|---------|---------------|-------------------|------------|---------------|-------
2 | discover | slave-01_controller | 1 | 10.108.20.134 | 64:df:89:aa:ad:7a | controller | | True
1 | ready | slave-04_compute | 1 | 10.108.20.3 | 72:fe:42:d2:cc:4c | compute | | True
4 | ready | slave-05_compute | 1 | 10.108.20.6 | 42:e4:79:46:bd:47 | compute | | True
3 | ready | slave-03_controller | 1 | 10.108.20.5 | 6a:58:24:b4:35:41 | controller | | True
5 | ready | slave-02_controller | 1 | 10.108.20.7 | 16:4a:1f:28:a2:41 | controller | | True
[root@nailgun ~]# ping node-1
ping: unknown host node-1
...
Also, I have rebooted server instance with id=2 and it boots into bootstrap instead of normal boot from HDD. You can see the result above in the fuel node output table.

[root@nailgun ~]# cat /etc/fuel/version.yaml
VERSION:
  feature_groups:
    - mirantis
  production: "docker"
  release: "5.1"
  api: "1.0"
  build_number: "499"
  build_id: "2014-09-05_00-01-17"
  astute_sha: "b622d9b36dbdd1e03b282b9ee5b7435ba649e711"
  fuellib_sha: "6ebadd157c5153e9bb3ed53fa73507a5c73572c3"
  ostf_sha: "f7b5d9d0d1cfaba5f1fe1e2c634493e92bce11db"
  nailgun_sha: "b36dccbc28584532ca1bdb679b096cc3f5f6f80a"
  fuelmain_sha: "b3afef75675ae3ab251a4f990f3432968eb746eb"