Product listing module misbehaves on vendor pages

SELECT DISTINCT b.* 
  FROM ceztt_hikashop_product_category AS a 
  LEFT JOIN ceztt_hikashop_product AS b 
  ON a.product_id=b.product_id 
  LEFT JOIN ceztt_hikamarket_vendor AS hikam_vendor 
  ON b.product_vendor_id = hikam_vendor.vendor_id  
  WHERE b.product_published=1 
  AND b.product_type = 'main' 
  AND a.category_id IN (32) 
  AND (b.product_access = 'all' OR b.product_access LIKE '%,9,%') 
  AND (hikam_vendor.vendor_published IS NULL OR hikam_vendor.vendor_published = 1) 
  AND b.product_vendor_id = 2 
  ORDER BY RAND() 
  LIMIT 0, 5

SELECT DISTINCT b.* 
  FROM ceztt_hikashop_product AS b 
  LEFT JOIN ceztt_hikamarket_vendor AS hikam_vendor 
  ON b.product_vendor_id = hikam_vendor.vendor_id  
  WHERE b.product_published=1 
  AND b.product_id IN (942) 
  AND b.product_type = 'main' 
  AND (b.product_access = 'all' OR b.product_access LIKE '%,9,%') 
  AND (hikam_vendor.vendor_published IS NULL OR hikam_vendor.vendor_published = 1) 
  ORDER BY b.product_price_percentage DESC 
  LIMIT 0, 5