verified, if you set to mono you receive a merged L and R signal to mono even if input is L or R (mono).
verify yourself putting on a stereo track two different sounds in L and R, e.g guitar pan L and Key pan R then get out to a patch point. you expeted that patch point input L (mono) send the guitar and the patch point R (mono) send a keyboard. but you'll find both L - R send both guit - key, merged in mono.
not shure if this is a bug introduced with new update. i worked with november update till last week, apparently without issue.
tested in another computer, same version 2020.01, same issue.