Solved!
This turned out to be a very interesting issue that took three separate Apple Support Advisers and myself to solve. In the end it was a combination of experimentation and a flexible thought process that found the issue and solution. The Apple Senior Advisor and I had a very valuable phone conversation while we experimented with this.
During the initial HomePod set up, I paired them as a stereo pair and temporarily placed them on my TV stand just to the right and left of the edges of the TV frame as my TV's width pretty much took up the entire width of the stand, there was barely enough room for the HomePods but I knew this was just a temporary setup. I have a Samsung flat screen TV and a 4th Gen Apple TV.
While playing movies via Netflix or Amazon prime, the movie would randomly pause and I would have to restart it by pressing Play. Drove us nuts. Then sometimes the HomePod on the right would intermittently start playing Apple Music radio out of the blue and I don't have an Apple Music subscription, it would do this while the left HomePod was still playing the movie soundtrack.
The first step in the troubleshooting process was to unpair the two so they were no longer a linked stereo pair and do a factory reset and set them up again but this time as two individual HomePods and retest. In doing this I found that it was the HomePod that was placed on the right side of the TV that was causing the pausing issue, the left HomePod would not pause the movies. Ok, this was good in that now I could focus on what was unique about the right HomePod.
When the right HomePod was deactivated from playing the movie soundtrack but still plugged into power, it would default automatically to playing Apple Music and it was a radio station that it would play. The Apple Senior advisor asked me to physically swap the left and right HomePods just to see if it may have been a WiFi issue. I told him that the two HomePods were three feet apart from each other and both were within 10 feet of my wireless router with nothing but air between them. We both then thought that swapping them would have no affect but decided to do it just for kicks since we were getting very close to having to send that right HomePod in for diagnosis, which I did NOT want to do. If the issue also swapped, we would then suspect that I may have a defective HomePod and if it did not swap, we would start focusing elsewhere.
So I swapped them but in the process of swapping them, I also did not place them on the TV stand where they were, I placed them a foot or two away from the TV stand so in essence I did two changes instead of just one. Then we retested and the auto pausing stopped happening. I walked over to the right HomePod (that used to be the left one), picked it up and placed it on the right side of the TV stand while a movie was playing and it auto paused immediately. Subsequent testing like this proved that it was the placement next to the TV that was causing some sort of interference with the functionality of the HomePod, but only on the right side of the TV so there must be something inside the TV casing on that side, like an antenna, magnet, power supply, etc that was electromagnetically confusing the HomePod.
Its been a day now and a couple of movies later and all is well. Sorry for the long winded post but hope this helps others who might be searching for a solution to an issue like mine.
