3000 MHz RAM interupts start-up

I've recently built a new computer. Here are the parts:

      ASRock Z370 ITX AC Motherboard
      Intel Core i5 8400
      Corsair SF450 450W SFX 80 Plus Gold Power Supply
      Corsair 16GB (2 x8) CMK16GX4M2B3000C15B DDR4 3000MHz RAM
      Samsung 1TB SSD 850 EVO
      MSI GeForce GTX 1070 Aero ITX OC 8GB Video Card

Now, I don't know much about RAM, so I was hoping that someone could tell me whether my computer is working properly, or if it has a problem. Here's what happening:

In the UEFI settings screen, if leave my RAM XMP profile on 'Auto' the computer will start normally with nothing strange, but the RAM will be set to 2133mhz. If I instead change it to "profile 1", it sets the RAM to 3000MHz, but it does something weird when the computer starts.

When the RAM is set to 3000MHz and I turn on the computer, it will turn for a few seconds, then restart, and then it will start normally. ie. it always switches itself off then on again after a couple of seconds before starting Windows. Once Windows loads, the computer seems to work properly and Windows reports that the RAM is running at 3000MHz. But I'm just a bit puzzled as to why it always turns off and on again. Is that normal? Do I need to change some settings?

As I said, it only does this on "profile 1", not on "auto". I didn't change any of the profile 1 settings, so I've assumed it's some default values that match my RAM.