Performance trouble - doing double search (maybe)

To get apachesolr_search.module to work, I had to add this line to the function "apachesolr_search_form_search_block_form_alter" :
$form['#action'] = url('search/apachesolr_search');

The three first lines of the function now looks like this:

function apachesolr_search_form_search_block_form_alter(&$form, $form_state) {
  if (variable_get('apachesolr_search_make_default', 0)) {
    $form['#action'] = url('search/apachesolr_search');

The reason for this, was that apachesolr always executed two searches after a search was made as can be seen from these screen shots.
First search:
http://img.skitch.com/20100822-fk4m2d7bcnrh53g8832h5jam6i.jpg
Second search, just following the first search:
http://img.skitch.com/20100822-ciauijb73bfbfs3ts73mu681q6.jpg

From the stack trace and the value for "action", the first search is executed because the search form is posted to the previous search url.

I've written "maybe" in the title, because I know we have done some hacking to the apachesolr modules to make them work with huge datasets (3-6 million nodes, 100.000-200.000 updated per day). So it might be that we have fucked up something while doing this. Please disregard this post if no one can reproduce this.