I don't think it's related to referral code in link.
Even if an article has URL references without the referral codes, it's still considered as plagiarism if few sentences in a row are exactly matched with other documents.
To avoid the issue, you should rephrase product description with your own words.
Ahhhhhh, you're totally right! Of course, I should have realised that myself.
I didn't want to muck it up, but I will in future provide my own take on the hunted item/app. Thanks for the clarification.