ZIP file is corrupt when using the Advanced Search (and unzip)

[vurt2]

When using the "Advanced Search" and selecting a least two contacts, a ZIP-file is generated that differs from the
file when using the modern (searchui) version of the search.

The file is bigger and corrupted, unzip is unable to unpack it.

I am using unzip on linux:
unzip -v
UnZip 6.00 of 20 April 2009, by Debian. Original by Info-ZIP.

unzip CiviOffice-Dokumente.zip Archive: CiviOffice-Dokumente.zip End-of-central-directory signature not found. Either this file is not a zipfile, or it constitutes one disk of a multi-part archive. In the latter case the central directory and zipfile comment will be found on the last disk(s) of this archive. unzip: cannot find zipfile directory in one of CiviOffice-Dokumente.zip or CiviOffice-Dokumente.zip.zip, and cannot find CiviOffice-Dokumente.zip.ZIP, period.

Unpacking with other, more modern (and more forgiving) programs works fine (like 7z x CiviOffice-Dokumente.zip).

The strange thing is that the files differ depending from which search you generate the zip - maybe one uses the commandline zip and the other the php extension?