When I install asus merlin on any of my ac68r routers i lose the guest wifi access in the gui only for the 5 ghz portion it is replaced with facebook wifi which i have never used. I have reset, factory reset but nothing seems to fix it I flash stock back and it works fine. this has been doing this for a while I cant say for sure when it started but its been about a year or more since I stopped using asus merlin for this reason and thought I would try it again to see if there was a firmware issue but it is still doing it with the latest version as of today.