Behat MinkExtension traversing, counting css-selectors

i need to test, how many css-selectors appear on webseite. I geht only huge array with nodes, which match on my condition. When i count rows within array, i get "five", but it schould be "three"

My code:

/**
 * @Then /^I should see more then one css slider-selector "([^"]*)"$/
 * @Then /^I should see more then one CSS slider-selector "([^"]*)"$/
 */
public function iShouldSeeMoreThenOneCssSliderSelector($css_selector) {
    $nodes = $this->getSession()->getPage()->findAll("css", $css_selector);

    $counter = 0;
    foreach($nodes as $row){
        if(!empty($row)) {$counter +=1;}
    }
    if($counter<2){
        throw new \Exception(sprintf("The page '%s' does not contain enough pictures for slider '%s'", $this->getSession()->getCurrentUrl(), $css_selector));
    }
}

But when i look on html-source, i have only three matches. This code tells, that i have 5 machtes. I guess, i don´t test correctly. Has anybody idea?