In AURA, you have a setting for Sync at Shutdown... here you can modify the behavior of the AURA Shutdown LED's.
I have an ASUS ROG Strix Z370-E, and they're basically the same, but look for a dropdown box on the "Color" section of AURA's Cycle Selection. If you "color by areas", you can select the RGB headers and most likely the RAM to Sync at Shutdown, but for some reason they have to be set in the "Sync All" Section of AURA First :S
[NOTE:] i have no RAM LED's but i do have a Cooler Master MA620P Twin Tower HSF with RGB LED, and i set it to "Breathe", and while i have "Rainbow" on the Rear IO Panel, the Cooler Master CPU HeatSinkFan still Breathes. just my experience, also it's a good idea to use the dropdown and configure the RGB headers to your preference in some of the Featured Presets ;). i believe the HSF breathes, while the Rear IO Panel is rainbow, because i used the "Color By Areas" in the Color Section dropdown, and modified the behavior in Sync All, first.