In RB,
It happens in the Track Type and the Audio Preferences.

If the target track type is stereo (right click the track and select Tack Type -> Audio stereo)you get a stereo track with both sides.
but
if the MONO input in Prefs is set to L/R (both channels) and the target track type is a MONO track .. you get 2 separate MONO tracks.

It's all in how you set up the RB recording session.
You can also set your default track type to stereo, so they start as a stereo audio track to begin with. That setting is in Options - Prefs - General tab labeled initial track type.
pics to follow

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RB-Input.jpg (128.83 KB, 31 downloads)

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