@Daniel-Golden-Cheetah-1316916967#271512 weet je toevallig of die partner een third party bank is?
What exactly do you mean by "third party"? It is a partner bank of bunq, so it is not bunq itself. In my own experience, the payments are sent by Community Federal Savings Bank's main office in New York. I didn't have any issues sending to any other US banks so far.
Because bunq has only branches inside the EU, they don't have the necessary license to operate as a bank in the US. For handling, sending and receiving currencies other than Euro, they work with a network of partners. Usually quite reliable, I have already paid also regular bills like rent, utilities, and other contracts in the US but also in Asian countries with this and nobody complained. Not sure what your specific use case is, though.