The strange behaviour is shown below:
# apt-get remove aqbanking-tools

Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer
required:
  libqbanking6
Use 'apt-get autoremove' to remove them.
The following extra packages will be installed:
  libqbanking6
The following packages will be REMOVED:
  aqbanking-tools libaqbanking20-plugins libaqbanking20-plugins-qt
The following NEW packages will be installed:
  libqbanking6
0 upgraded, 1 newly installed, 3 to remove and 313 not upgraded.
Need to get 238kB of archives.
After this operation, 737kB disk space will be freed.
Do you want to continue [Y/n]?

apt-get suggest removing the package "libqbanking6", but the package is
not installed, apt-get is installing it for unknown reasons! It is not
required by any installed package.

If one asks to remove it too:

# apt-get remove aqbanking-tools libqbanking6
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package libqbanking6 is not installed, so not removed
The following packages will be REMOVED:
  aqbanking-tools libaqbanking20-plugins libaqbanking20-plugins-qt
0 upgraded, 0 newly installed, 3 to remove and 313 not upgraded.
After this operation, 1483kB disk space will be freed.
Do you want to continue [Y/n]?

apt-get works smoothly.

Versions are:
# dpkg -l aqbanking-tools libaqbanking20-plugins libaqbanking20-plugins-qt
[...]
ii  aqbanking-tool 3.7.2-1        basic command line homebanking utilities
ii  libaqbanking20 3.7.2-1        plugins needed by libaqbanking20
ii  libaqbanking20 3.7.2-1        plugins needed by libaqbanking20


Regards,
Marco
-- Package-specific info:

Maybe I understand how the problem emerge. Here is another example:

I try to remove a package, and apt-get installs the NEW package libbluetooth3
and suggest removing it...

# apt-get --purge remove openbios-ppc
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
  libbluetooth3
Use 'apt-get autoremove' to remove them.
The following extra packages will be installed:
  bochsbios libbluetooth3 libpulse0
Suggested packages:
  pulseaudio
The following packages will be REMOVED:
  openbios-ppc* qemu*
The following NEW packages will be installed:
  libbluetooth3
The following packages will be upgraded:
  bochsbios libpulse0
2 upgraded, 1 newly installed, 2 to remove and 1161 not upgraded.
Need to get 552kB of archives.
After this operation, 44.8MB disk space will be freed.
Do you want to continue [Y/n]? n
Abort.


Removing openbios-ppc, apt also has to remove qemu. But qemu is not up-to-date,
so apt tries to update qemu. This operation requires updating bochsbios and
libpulse0, and installing libbluetooth3. But also the last version of qemu
depend on openbios-ppc, it must be removed... Nevertheless apt keeps on
updating and installing the related but unneeded packages.

One more question arises... If I try to update qemu, apt updates and installs packages as above, and suggest removing libbluetooth2!

# apt-get install qemu
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
  libbluetooth2
Use 'apt-get autoremove' to remove them.
The following extra packages will be installed:
  bochsbios libbluetooth3 libpulse0
Suggested packages:
  pulseaudio samba
The following NEW packages will be installed:
  libbluetooth3
The following packages will be upgraded:
  bochsbios libpulse0 qemu
3 upgraded, 1 newly installed, 0 to remove and 1162 not upgraded.

This means that BOTH libbluetooth2 and the newly installed libbluetooth3 should
be auto-removed after removing openbios-ppc, isn't it?

Version of related installed packages are:
ii  bochsbios        2.3.7-1          BIOS for the Bochs emulator
ii  libpulse0        0.9.14-2         PulseAudio client libraries
ii  openbios-ppc     1.0-2            PowerPC Open Firmware
ii  qemu             0.10.2-2         fast processor emulator

Best regards,
Marco

It seems that this bug and the bug #519469 are the same
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=519469

Both arise because apt installs and suggest removing a package. We should
merge 517202 519469

Regards,
Marco

merge 517202 519469
thanks

Hi Marco!

Sorry for the delay, I completely missed your mail.

Done, thank you for the catch.

Thx, bye,
Gismo / Luca