Thank-you everyone, for your replies.
My little problem reminds me of when I take my car to the mechanic and say "It's making a strange sound. What's wrong?"
And the mechanic says "Let's go for a drive and I'll listen."
But the car runs normally and refuses to demonstrate the annoying noise to the mechanic!
Then, to make matters worse, the sound returns as I drive home!
At 9:20:00 AM Greenwich Mean Time, everything was hunky-dory.
10 minutes later, the site was as slow as molasses.
Now, everything is fine again.
The problem seems to be sporadic and I haven't recognized a pattern or cause.
I guess I'll just do what I usually do: ignore it and hope the problem goes away.
Windows 10 Home, 64 bit, Winamp 5.666, Bento Skin