I haven't found in the datasheet any info about this DAC's SPI power-up time delay.. There is only "Power-Up Time: 4 us", but its not specified there, whether it is applicable also to the SPI control.
The thing is when I used 200 us start delay, the SPI writes hadn't any impact. My SPI init command are: set internal reference on, set DAC channels to some non zero values.
When I use 400 us start delay it works just fine.