Buy Now button - Out of stock delayed update issue

[Clifton]

When a product is bought and there are no remaining stock the buy button is set up to become inactive and changes to out of stock image. The button becomes inactive as soon as the purchase is made which is correct, but the issues is the image does not change instantly/properly.

 

It some times does change on the product page.

It some times change if you refresh in the search results list.

And it hardly ever changes in the home page latest products list.

 

Is this related to browser caching? which files should I check that they contain all the right code?

 

Any idea how I can solve this? It is important that the product shows out of stock (sold) as we are selling individual unique items and we have many people trying to buy the same product at the same time.

 

Any help I would be very appreciative.

 

Cliff

 

(running PrestaShop 1.6.0.14 at present)