*** THE PROBLEM HAS BEEN SOLVED! ***
As directed by a savvy forum member at the JRiver Interact Users Forum, I went into Services and scrolled down to Dell TechHub, right-clicked and opened Properties and changed Startup Type from Automatic to Disabled, and then stopped the service. At 11:59 AM I opened JRiver MC35 and started playing a song file. The computer clock flipped over to 12:00 PM and for the first time there was no playback hiccup as the song kept playing flawlessly. I checked Event Log and that NTFS event that has been appearing every day at between ten and nineteen seconds past 12:00:00 PM was not listed there in the Windows System events!
Now I finally know what is behind this issue and how to eliminate it!
Unfortunately (predictably), my Dell applications will not function properly when Dell TechHub is disabled or stopped, so if I want to launch Dell Optimizer or Dell Command | Update or check for updates in Dell SupportAssist, I must start the service and set Startup Type back to Automatic.
Since this shadow copy event triggered by Dell TechHub only happens at 12:00 PM (insofar as I've noticed, that is... it may be triggered at other hours but that remains to be seen, next time I hear a playback glitch in JRiver), the easiest solution is for me to leave Dell TechHub startup set to Automatic, and if I am going to be playing music in JRiver at the 12:00 noon hour, to disable it first, and reset it to Automatic after the twelve o'clock hour is passed. Or I could just leave it disabled and then reset it whenever I want to launch a Dell app for updates or scans.
I do use SupportAssist once or twice a week to check for updates to BIOS and drivers and to scan for hardware issues. I seldom use Command | Update or Dell Optimizer so I should probably just go ahead and uninstall those programs until I see a need for having them on my PC.
Thanks again to all of you who took the time to help me troubleshoot this matter and especially to
@tzr916 for pointing me to the solution!