I had that exact kit and found it was selective on BIOS versions... Worked fine until I updated to the recent BIOS builds. The last 2 wouldn't post at all with 3600 for me. I could only post at default JEDEC DDR4 speeds. I ended up selling it to a Ryzen user and switching to Samsung B Die.
That kit is better served with Ryzen. Asus didn't really do much testing, if any, with that particular Hynix kit on intel platforms.
i had ram showing 3466mhz and when i started my PC it showed around 2000mhz frequency. I was able to get it to what the package said by going into bios and changing a setting so it uses DOCP configuration/profle. This sets up the RAM to work at its full potential.