Prevent repeat write API calls whilst traffic mirroring

I'm looking at using traffic mirroring with Istio to dark test releases.

The mirror'd traffic will mean write APIs like order & payment, etc are called multiple times which I don't want else I'll be charging the customer twice & sending them a duplicate product.

Is there a standard way to prevent this (stubbing seems an odd thing to do in production) or is mirroring only really applicable for read APIs?