Temporary product reservation when adding product to basket doesn't go away anymore

[Oli4CH]

I have a few products that still have the status "reserved" eventhough there is not a single open order. All orders in the backend are either closed/delivered or cancelled.
I have that issue now for months and I didn't find any solution to change it.

How and where can I get rid of it as stock information is always wrong for those products?

Any help is highly appreciated.
Thanks in advance.

[Oli4CH]

Is there really no one who can answer my question?
I'm pretty sure this topic can be solved fairly easy...

[musicmaster]

Are you sure that "reserved" doesn't come from some special module?

[Oli4CH]

Thanks @musicmaster for your feedback. Yes, I am 100% sure.
I was now going through 200 orders and I found orders where the customer got his refund but the order itself wasn't partially cancelled. The order was initially delivered.
This seems to be the cause of the reserved products.
What I now did, was cancelling these orders or partially cancelling it.

I was looking for aanother and much faster approach as this was extremely time consuming.
Right now, this topic is solved for me but it might be helpful for others if there will be a different approach than what I did, especially if you have much more orders to check.

Do you know if there is a possibility to somehow determine to which order a reserved product belongs? That would speed up the process massively.

[Anfuca]

Very careful with the module Temporary product reservartion: 
https://addons.prestashop.com/en/stock-supplier-management/21707-temporary-product-reservation-lonely-stock.html

It has several perfomance issues and your website will go down