latest bios and idcc installed?
Yes, absolutely, I’m a tech myself this is a manufactory problem and sound to me, I’m not alone who is experiencing this problem.
I would highly suspect the issue is that the fans you are using (particularly for larger fan sizes) require more startup voltage then the board is providing at boot time... this probably only applies to the 3-pin headers on the board. You would have to measure the output at the connectors to validate this... some manufacturers get around this by forcing maximum signal for a few seconds right after startup... some do not. (Sometimes you can actually spin the fan by hand and get it to start in these cases).
Anyway, without direct measurements that would be the most likely scenario (I use an external fan controller rather then the 3pin headers on the DX58SO).