I have an R8000 router and for a short time I had used a USB adaptor for WiFi on my main machine, I have since gotten rid of it and am using Wired. My issue is I can't seem to get RID of the information? maybe it doesn't matter but it sure irritates me 🙂
As a guess a factory reset would work. Backup your configuration first. It shouldn't cause issues by being there though... my asus router remembers all past devices that were connected previously.
