Went to Walmart and bought a RT-AC68R. It serves as a media bridge to the RT-AC88U just fine. No intermittent disconnects. I guess a Netgear can't serve as a media bridge to an ASUS even though it works fine the other way around. The speeds were pretty fast between the two ASUS routers. I was able to transfer a 3GB file in about 42 seconds from my WD Mycloud to my PC. From my gaming PC to my HTPC the same file took 25 seconds.
When my second RT-AC88U comes in the mail from Newegg I'll just take this Walmart router back.
When my second RT-AC88U comes in the mail from Newegg I'll just take this Walmart router back.