If derivative arises on a credit purchase from overseas counterparty?

Dear Friends,

Today I had revision course of the P2 exam. In the course of study we solved the question about some US company (USD is functional c-cy), which bought some goods from the other US company (USD is functional c-cy), but the account payable is EUR nominated. The tutor said that this transaction gives rise to embedded derivative, as the EUR is not a functional c-cy for both seller and buyer.
I asked him, if the embedded derivative would arise to the buyer giving the EUR to be functional c-cy of the seller. He replies than no, but could not explain why.
As far as I understand, it is doesnt matter to the buyer what functional c-cy will seller have untill the anount due in local c-cy will vary due to the currency ex-rate dynamic. In each case such a contract is a derivative. What do you think?