dpkg bug regarding dependencies?

[Wolfgang Karall <lists+debian-user@karall-edv.at>]

Hello,

when trying to work around
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=620088 I downgraded
nfs-common to the version in testing, which actually worked, even though
nfs-kernel-server has a versioned dependency on nfs-common (see below), 
is this a bug in dpkg or did I miss something regarding the versioned
dependency handling?

I actually only noticed since "aptitude forbid-version" did bail out
telling me that there is a dependency problem.

Cheers
Wolfgang

PS: the shell output:

x61s:~# apt-cache policy nfs-common nfs-kernel-server 
nfs-common:
  Installed: 1:1.2.3-1
  Candidate: 1:1.2.3-1
  Version table:
 *** 1:1.2.3-1 0
        500 http://ftp.at.debian.org/debian/ sid/main i386 Packages
        100 /var/lib/dpkg/status
nfs-kernel-server:
  Installed: 1:1.2.3-1
  Candidate: 1:1.2.3-1
  Version table:
 *** 1:1.2.3-1 0
        500 http://ftp.at.debian.org/debian/ sid/main i386 Packages
        100 /var/lib/dpkg/status
x61s:~# apt-cache show nfs-kernel-server | grep ^Depends
Depends: libblkid1 (>= 2.16), libc6 (>= 2.3), libcomerr2 (>= 1.01),
libgssapi-krb5-2 (>= 1.6.dfsg.2), libgssglue1, libk5crypto3 (>=
1.6.dfsg.2), libkrb5-3 (>= 1.6.dfsg.2), libnfsidmap2, libtirpc1,
libwrap0 (>= 7.6-4~), nfs-common (= 1:1.2.3-1), ucf, lsb-base (>=
1.3-9ubuntu3)
x61s:~# dpkg -i nfs-common_1.2.2-5_i386.deb 
dpkg: warning: downgrading nfs-common from 1:1.2.3-1 to 1:1.2.2-5.
(Reading database ... 177879 files and directories currently installed.)
Preparing to replace nfs-common 1:1.2.3-1 (using
nfs-common_1.2.2-5_i386.deb) ...
Unpacking replacement nfs-common ...
Setting up nfs-common (1:1.2.2-5) ...
Installing new version of config file /etc/init.d/nfs-common ...
Stopping NFS common utilities: statd.
Starting NFS common utilities: statd.
Processing triggers for man-db ...
x61s:~#