About the Outtage...

@TP-Link I am running the internet connection monitor  chrome extension on 5 laptops in my home.  This browser extension pings www.google.com every 3 seconds.  And it logs all outtages.  I am also running this browser extension on my desktop machine.  In addition to that, I have an envisalink home security device that gets pinged by an off premise watch dog service every 5 minutes.  These 7 devices (laptops, desktop, security device) are distributed across 3 deco x60 nodes.  The desktop machine is the only device that is wired in via Ethernet to the router node.  The rest are connected wirelessly.  Every device except the desktop machine showed the 27 minute outtage at 1:32AM EST on April 27th.

About the Log...

It is currently 7:59AM EST in Michigan.  When I open the "system log" via the web interface (http://192.168.1.1/webpages/index.html#sysLog), it only goes back as far as 6:08AM EST this morning.  It does this for all types of log levels (NOTICE, ERROR, WARNING, etc).  The device was last restarted yesterday (April 27th) at 3:09PM EST.  When I hit the refresh button on the browser, the log now only goes back to 6:12AMEST.  (It took me 3 minutes to write this paragraph.). So my deco system is only storing 1 hour and 51 seconds worth of activity.  Which isn't enough for me to diagnose what went wrong on April 27th at 1:32AM EST  

Thank you very much for your timely reply!!!!

Eventhough I can't get any information from the Deco logs, the attached Macbook logs paint a picture of what happened

01:32:23 - Macbook detects that c0:c9:e3:3:38:67 node has gone "INACTIVE".   This MAC address is for the node currently acting as a "router"

01:32:25 - Macbook quickly fails over to c0:c9:e3:3:38:63 node.  But, its DHCP requests go unanswered for next 27 minutes

01:59:04 - Macbook later detects that c0:c9:e3:3:38:67 (router node) is"ACTIVE" again, and switches to it. 

01:59:04 - DHCP then is able to properly assign an IP address.

This suggests that whatever occurred happened to the network likely occured within the main router node.  A cable modem or ISP failure would have still resulted in DHCP succeeding.  And, the fact that the connection properly failed over to c0:c9:e3:3:38:63 suggests failure wasn't at some other point within the network. 

As a test, I unplugged the ethernet cord attached to the first non-managed switch and all clients failed over to the main router within 2-3 seconds not 27 minutes.  Which further indicates the failure happened within the primary deco node acting as a router.

The logs also show that DHCP doesn't succeed until  c0:c9:e3:3:38:67 (router node) is ACTIVE again.  Which again suggests that the router node went completely dormant for 27 minutes.  Only when it presented itself as "active" was the network able to properly function again.

@TP-Link 
1.) You are correct, the Macbook is stationary. 
From Office Node (Main Router)
Mac Address:c0:c9:e3:03:38:67 for 5Ghz Antenna
It is located about 15 feet from office with 2 walls inbetween.  
Signal Strenth registers at 81%
From Bedroom Node (Satalite Access Point)
Mac Address:c0:c9:e3:03:38:63 for 5Ghz Antenna
It is located about 20 feet from office with 2 walls inbetween.  
Signal Strenth registers at 77%

I can see from the Mac that band steering does cause the signal to jump from 1 node to another from time to time.  But, I never see a BBSID go "inactive".  That only occurs when I restart a node or unplug the node.  

2.)  This was a 1 time event.  I installed the deco X60 mesh network on April 15th.  The outtage occured on April 27th.  I've had other minor blips (loss of connection for 3 seconds), but nothing that lasted 30 minutes.  This is the only time that occurred.