Using a weak autosensing bidirectional level translator for a UART is moronic*. Why not simply use unidirectional level shifting buffers?
If you don't need to handle logic levels above 5.5V or below 1.65V Vcc, 74LVC1T45 is suitable, with its direction pin tied high or low to make it unidirectional (or 74LVC2T45 if you need two lines in each direction). They are good for +/-24mA drive @3.3V, so it would probably be a good idea to add series 330R resistors on the target side if its a MCU under development to limit the current in the case of bus contention due to improper I/O initialisation. They also go tristate on partial power down, so if you tap target side power from the target, you don't have to worry about what happens if the target looses power while the FT2232H is powered by USB or visa versa.
If you need to go below 1.65V, I'm sure someone else will suggest an alternative.
* Even for a USART in synchronous mode its fairly dumb if there is any possibility of providing control lines for data direction and clock as master (out) or slave (in).