Going Crazy with ocassional audio drops

Sonos users for several years now and Would really appreciate some help as I am going crazy.

Background:

Sonos Wireless Network working flawlessly for several years

Problem:

Music drops out for a few seconds then comes back on. The audio can often be perfect for prolonged period then begin acting up.

Internet Radio or Sirius Radio streaming does not suffer from any dropouts.


System Setup:

Associated ZP: 192.168.0.123
---------------------------------
CONNECT:AMP: Living Room
Version: 3.8 (build 19353220b)
Hardware Version: 1.16.3.1-1
IP Address: 192.168.0.123
OTP: 1.1.1(1-16-3-0.9)
---------------------------------
PLAY:3: Master Bedroom
Version: 3.8 (build 19353220b)
Hardware Version: 1.8.1.2-1
IP Address: 192.168.0.138
OTP:
---------------------------------
PLAY:5: Portable
Version: 3.8 (build 19353220b)
Hardware Version: 1.16.4.1-1
IP Address: 192.168.0.118
OTP: 1.1.1(1-16-4-zp5s-0.5)
---------------------------------
CONNECT: TV Room
Version: 3.8 (build 19353220b)
Hardware Version: 1.1.16.4-1
IP Address: 192.168.0.117
r8: 16.0-7

Airport Express Connected to ZP 120
Audio Compression: Uncompressed
Wireless Channel: 11


Troubleshooting Done:

• Network? - No apparent bandwidth issues. When its working, I can stream two HD Videos to two computers and run Sonos without a problem. In addition, I can stream Internet Radio or Sirius XM to Sonos without an issue.
  
• Windows Home Server? - Appears to be working fine. Again, I can stream HD Video or work on Server while streaming HD Video and everything is fine. CPU usage on Server is neglible even when streaming HD Video and Sonos.
  
• Problem with ZP 90? - I changed the wired connection to the Play 5 and problems continue.
  
• Sonos Error Log - nothing recorded
  
• Wireless Channel - Dropouts occured on player which is hardwired also.

Thanks in advance for any suggestions on how to resolve this issue.