Script issue Bigcommerce purchase event

Hi, I am working on a Bigcommerce website built-in stencil theme. I set up Conversion API successfully in all events with bigcommerce script. Now Only purchase event getting an error of product id in data layer I found SKU as product id. In all other events, product is
match with the catalog but in the purchase product id not match because of ok SKU. Please help me to solve this issue.

It appears that there is an issue with the dataLayer event purchase on your site. This problem does not have anything to do with our scripts or ss tracking, so I suggest contacting whoever set up the purchase event in Data Layer and ask them about changing id variable.

Thank you so much for your valuable opinion

I am also facing the same issue.