As far as I’m aware, there is no way for the motherboard and power supply to communicate. There are no dedicated communication channels on the 24 pin MoBo connector, for example, so as long as this power supply does not have it’s own unique connector, there’s no way for your OS or BIOS to tell it how to run the fan. This means the power supply itself is determining that the fans need to run at 100%. If this is happening often, then yes, I think something is wrong with it.
Honestly, I don’t think I’ve ever heard my PSU fan. It’s always quieter than the case fans and CPU fans.