TXB0104: Open-drain / Push-pull application

Hi 

I'd like to know why TXB is not applicable to open-drain and why TXS  is not applicable to push-pull, could you please explain it in a way of circuitry?

I use TXB0104 in SoC multi-function pin which can be configured as SPI or GPIO interface, if it works as SPI interface, TXB0104 is fine, but TXB0104 become abnormal once the pin configured as GPIO function.

I guess the issue is caused by the GPIO open-drain mechanism.

thanks.