Sonar Platinum - hesitation on playback or record

This is a tough one to describe and, IMHO, a very strange issue.
 
Recently, my previously smoothly working Sonar Platinum / Scarlett 18i20 (Ver 1) setup has developed a very irritating issue. Occasionally (not always, and not under predictable circumstances), when I press Play/Pause (from the control bar or space bar... any means of starting and stopping) and whether record is armed or not, Sonar will pause for maybe 1.5 seconds before the timeline begins to move... and there's no audio sent to the Scarlett interface.
 
Of course, I don't have any way to know where the data flow stops. But here's the VERY strange thing... if I switch to ANY other application -- let's say Windows Explorer -- then switch back to Sonar, there's a brief sound --often a reverb decay, but not limited to this -- and then Sonar works normally. That's all I have to do to break out is to focus another application.
 
In a few instances, Sonar has stopped a couple of seconds into playback. Sometime, it works properly for hours at a time, only to go through a period of bad behavior. Sometimes, it does this immediately after launch... new projects, old projects, simple projects, complex project, 24bit, 26bit, 441Hkz, 48KHz... I've tried all manner of configuration variants.
 
I've not ruled out an issue with Scarlett (ASIO) and Windows 10 (64bit Pro), but there's no reported driver crash and switching to the Scarlett MixControl is just like switching to any other app -- it restarts the connection.
 
So... I'm asking, does anyone have ANY ideas??? WTF???
 
Here's a brief summary of my computer setup:
 
OS Name    Microsoft Windows 10 Pro    
Version    10.0.14393 Build 14393    
System Type    x64-based PC    
Processor    Intel(R) Core(TM) i7-4930K CPU @ 3.40GHz, 3401 Mhz, 6 Core(s), 12 Logical Processor(s)    
BIOS Version/Date    American Megatrends Inc. 4.6.5, 10/16/2014    
SMBIOS Version    2.7    
BaseBoard Manufacturer    EVGA    
Platform Role    Desktop    
Installed Physical Memory (RAM)    16.0 GB    
Total Physical Memory    15.9 GB    
Available Physical Memory    11.3 GB    
Total Virtual Memory    31.9 GB    
Available Virtual Memory    26.0 GB    
Page File Space    16.0 GB    
NVIDIA GeForce GTX 960

M... thanks for the thoughtful reply. Although I try to keep the environment pristine -- no updaters or other CPU or IRQ hogs -- that's always a possibility. However, in this case, task manager shows nothing.
 
I moved the Scarlett 18i20 to another USB hub... it was in a USB3.0/2.0 tree. So far, so good, however part of the frustration of seeking a solution is that it is sporadic. I can't just test and say go or no go... you just have to continue working, wait and see. My thinking is that it shared the USB3.0/2.0 with a USB 3.0 drive. I don't know how Windows services the USB Read/Write, but possibly the hard drive was given precedence. Grasping at straws, but it seems to be working at the moment.

I have had a few odd problems with Sonar. I have solved them by Rolling back my version and then putting it back to the version I had been using. This has always worked for me.