The datasheet says "GPO/GPI commands will override and corrupt an I2C/UART command in progress", here's what that means.
On GMSL1 parts, reverse channel (deserializer to serializer) data and changes in the GPI pin, share the same data path. Therefore, the microcontroller controlling the parts needs to disable one feature when the other is being used. See "GPI to GPO Delay" in the data sheet for how long to disable data when a GPI transition happens.