..The transaction was automatically routed through the US, possibly because of the USD currency used in the transaction, which is how the United States was able to seize the funds.." [0]

Also: "The U.S. Office of Foreign Asset Control (OFAC) enforces U.S. economic sanctions programs ... and any person or entity physically located in the United States (including branches of foreign corporations)" [2]. And most foreign banks do have US branches. And if transaction is in US Dollars, OFAC applies too [1]. I can dig deeper, down the rabbit hole :)

All right. Seems like if a transaction involves USD, it must pass US based correspondent bank.

[0] https://en.wikipedia.org/wiki/Society_for_Worldwide_Interban...

[1] https://nacm.org/pdfs/webinars/FCIBWebinar_Compliance_OFAC_U...

[2] https://www.riskscreen.com/kyc360/of-counsel/ofac-compliance...