Rear speakers duplicating main speaker sound from TV source?

what rear speakers?

I do have rear surround speakers but they only play when I have a dolby 5+ channel feed through a totally different signal path.

So I'm guessing you have your AV reciever set to something like "all channel stereo" where it sends a signal to all the speakers.  I think I've seen that on my Denon but never used it.  It would be up to the OEM how they managed that so get your user manual out.

Jerry

I would think you rear speakers would pick up some thing when you set receiver to surround mode even when getting a stereo signal.

I have learned that a 5.1 Signal does come from the networks but it's hard to really understand how consistent this is.

The original question leaves out a lot of info, but NO is the easy answer. We assume you have an AV receiver and multi-channel capability. These multi-channel audio programs send a specific range of sounds to specific channels to simulate you being right there in the action (hard to believe in 2023 we need to explain this). When playing multi-channel content such as from TV or movies, you set the decoder/system to play the way you want, by the chosen decoder such as Dolby Surround. You can also play 2-channel stereo through all the speakers by again choosing the option for the decoder to "simulate" surround sounds and send content to all the speakers, creating an artificial surround but not really surround.