i see that your problem with cache-file is very old and fixed many monthes ago.
Also i see that 1.1.9 already contain fix of it. But in your case it is not .
Please check file public_html/storefront/model/catalog/product.php
method getProductsAllInfo line 1187 (+/-).
You must to see in it
$output = $this->cache->get('product.all_info.'.md5(implode('',$products)).'.'.$customer_group_id,$language_id,$store_id );
and see belong
$this->cache->set('product.all_info.' . md5(implode('',$products)) . '.'.$customer_group_id, $output, $this->config->get('storefront_language_id'), (int)$this->config->get('config_store_id') );
in both cases you must to have md5 call inside cache name. If you don't, just comment those lines with //