ADXL357 synchronization related question

When configurating the ADXL357 device in a way of EXT_SYNC = 10, EXT_CLK = 0 with a SYNC signal that Over 4000Hz, what will happen in this case in term of behavior, will the device ignore the previous SYNC signal and fail to output data ,or it will ignore the current SYNC signal that it is over 4K update rate and keep outputting the data in the maximum 4K sample rate?