Just as an FYI, we get FSR on channel 409 on Rogers. The channel does have a properly encoded DD5.1 signal, with the dialogue coming out the centre channel, etc. I just checked on some drag racing programme.
It is possible that if the original programme is not DD5.1, they may still send DD5.1 that is "improperly encoded" - see more on that topic below:
Here's an FAQ on DD5.1 and the fact that some programming on CBC, etc is often what I call "improperly encoded" since they send a DD5.1 signal all the time, but only the LF & RF channels on programming that was not DD5.1 to begin with:
Items 1, 3, etc.
So, a DD5.1 signal is no guarantee that you will get centre channel sound, if it's improperly encoded. Of course if the channel is sending DD2.0, then most AVRs will decode that using DPLII, etc to give you surround sound and centre channel audio, however, if you're getting DD5.1 that's improperly encoded, there's usually not much that you can do, other than change the output of the STB for that particular channel to two channel audio, in which case you'd have to change it back for other channels, or utilize analogue audio connections and switch the AVR to that input, both of which are not great options.
If the problem persists, you may wish to contact Bell and the "broadcaster" in question. I have not found Bell very responsive, however, I have found the broadcasters helpful in some cases.