The first thing to do for this is that you make sure that the inventory isn’t expired even if you know, ask Amazon to check and show you images, then you can provide Amazon with the appropriate evidence that it is a misunderstanding and your inventory isn’t expired.
You need to provide the evidence of the product’s expiration date. Provide evidence of expiration exact date to Amazon with documentation that proves your product is not expired. This could include the manufacturing date, the expiration date, or other relevant documentation.
If something like that happens again and again then you need to check whether there is a manufacturing and expiry date on the backend of your listing or not through which Amazon determines your product as expired.