Cuemix send only on tracks routed directly to the Main Out?????

I can only seem to find the Cuemix sends on tracks that are directly routed to the Main Out bus. Is this due to technical reasons, or is it some settings/options that I'm not aware of?

I have set up a song (for feature use as a template), with many different groups/busses. I have routed a set of default tracks (ie 14 drum tracks and so on) to their respective busses. All good so far.

But it seems that I have to re-route all my tracks to the Main Out to get the Cuemix sends available on these tracks.
Is it so, or is it me

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