When adding a mono send from one track to another and choosing "New channels on receiving track" the channel count on the receiver does not get increased. Instead it is blanked out.
Here I set up a send from Track 3 to Track 2, choosing to send mono on channel 3. As we see when opening the routing for TRack 2, its channel count is blank. I expected a 4 there.
Strange thing, the send still works, unless the two tracks get copied, which is when the issue described here
https://forum.cockos.com/showthread.php?p=2192402 arises.
In the gif above, both tracks 2 and 3 are in the same folder underneath track 1 (maybe that matters)