I again booked several pre-paid stays at two Thai Accor properties and it seems it is Pullman King Power Bangkok who charges directly in the credit card's currency.

I believe it is against Accor's rules:
5. All reservations, regardless of their origin, are payable in the hotel's local currency unless specifically indicated otherwise at the hotel.

There is also no reference to the original currency amount, thus I do not know how much THB I was charged and I checked the exchange rate against the booked amount: bad exchange rate.

I sent them a mail asking explanations.
I will post their reply here.