External search not always working

[kosarko]

With the following corplist:

<?xml version="1.0"?>
  <corplist name="root">
    <corplist name="LINDAT speech corpora">
            <keywords>
                <keyword ident="teitok" color="#ff4800">
                        <label lang="cs">TeiTok</label>
                        <label lang="en">TeiTok</label>
                </keyword>
            </keywords>
      <corpus ident="ovm_cs_w" sentence_struct="seg" num_tag_pos="16" keyboard_lang="cs" repo="http://hdl.handle.net/11858/00-097C-0000-000D-EC98-3" speech_segment="seg.soundfile" features="words only"/>
      <!-- features attribute is needed! -->
      <corpus ident="tt_mycorpus" sentence_struct="text" num_tag_pos="16" keyboard_lang="cs" features="words only">
              <metadata>
                      <keywords>
                              <item>teitok</item>
                      </keywords>
              </metadata>
         <token_connect>
                        <provider>wiktionary_example</provider>
         </token_connect>
      </corpus>
    </corplist>
  </corplist>

I can see that the keyword is assigned correctly:

It filters correctly if I click the keyword, but shows nothing when I use the url param keyword=teitok