Wow, I literally can't find an exact indication of what's going on.
So far it appears:
1. Q-LED yellow means the system memory (DDR4)
2. SOLID yellow may mean good, but BLINKING may mean bad
3. unsure if yellow LED is just for POST then meant to go away when you boot into Windows
*so it MIGHT be fine... if MEMTEST86 passes I don't think there's any problem but either way I'd contact Asus' Tech Support (well, run MEMTEST86 first and if there's a problem troubleshoot one stick at a time)