Sure, do bear in mind that with every new release of the plugin you will have to make the changes again or never install new releases anymore.
Now with regards to the changes that need to be made, go to this PHP file:
../wp-content/plugins/woo-product-feed-pro/classes/class-get-products.php
On line 2393 you will find this piece of code:
// Make sure we do not process duplicate products that are already feed
// $channel_hash = $project_config['channel_hash'];
// $channel_duplicates = "woosea_duplicates_".$channel_hash;
// $prevent_duplicates = get_option($channel_duplicates);
// if(empty($prevent_duplicates)){
// $prevent_duplicates = array();
// $fake_id = 99999999;
// array_push($prevent_duplicates, $fake_id);
// update_option($channel_duplicates, $prevent_duplicates, 'no');
//}
Remove all the // apart from the first line of the above code.
On line 2423 you will find this code:
// Add to the prevent duplication array
// if(!in_array($product_data['id'], $prevent_duplicates)){
// array_push($prevent_duplicates, $product_data['id']);
//} else {
// // duplicate product, do not add
// continue;
//}
Again remove all // apart from the first line of the above code and 5th line
And on line 4863 you will find this code:
// Add processed products to array
//if(get_option('woosea_duplicates')){
// update_option($channel_duplicates, $prevent_duplicates, 'no');
//}
Again remove all // apart from the first line again
On line 4978 you will find this code:
// Delete processed product array for preventing duplicates
// $channel_duplicates = "woosea_duplicates_".$project_hash;
// delete_option($channel_duplicates);
Again remove all // apart from the first line again
On line 5032 you will find this code:
// Delete processed product array for preventing duplicates
// $channel_duplicates = “woosea_duplicates_”.$project_hash;
// delete_option($channel_duplicates);
Again remove all // apart from the first line again
That should do the trick. Please bear in mind that this feature has only been tested for over a week and was causing issues so we cannot offer you support on it.