Thanks to all who weighed in. I contacted SVS who asked me to send them an audio file of the issue. That was not an option as the problem was intermittent and I was not in a big hurry to try to reproduce it as I felt I’d be damaging the sub. I had unplugged the sub and taken it out of the system as a precaution.
I plugged it back in to see if that reset had made a difference. Apparently it had? The intermittent problem is no longer. At least for now.
Perhaps an issue with static in this dry winter? Who knows. I’m good for now and appreciate all of you adding ideas.
Frank