It seems particularly salient that, near as I can tell, Citi paid the money out of its own funds, not using Revlon funds it was holding in reserve. In which case it was not paying money that Revlon owed, it was accidentally giving Brigade an amount of its own money equal to what Revlon owe, not even immediately but in the future.

If my understanding it correct, it would seem to be Citi's mistake, leaving them on the hook rather than Revlon.