I'm running this code on my ListProduct page and the first time I get to the page, I might get 4 items. Then if I refresh the page, I'll get 6, then 4, then 5...etc I can't see any reason for this. I checked my query and it's always the same. If someone could point me in the right direction, that would be helpful.
$products = $layer->getProductCollection()
->addAttributeToFilter('part_number',array('in'=>$numbers))
->setVisibility($this->productVisibility->getVisibleInSiteIds());