The product quantity changed without any notice

Dear Sellers.

I have found a changes in the listed product quantity without any notice today.

I have been selling for year the same product according to listing. It was 1 quantity per order. But now it shows 4 packs per order. I have changed it to 1 but that's not showing in the as originally after I edited. Still showing 4 count. What should I do ? How that possible this kind of things happens to the ASIN ?

This kind of error effect my CX performance. Could you please advice me how to change bank to original listed ASIN. Because I can see in the detail page that 1 pack in one place and another place 4 quantity which visible to customer that 4 count quantity.

Very stressful see this error.

Please advice me how to fix this ASIN issue.

Thank you

Kind regards