This is an old one that annoys me since quite some time, but I just found out today what actually happens. Tested in NU 10.2.20 under Win 7.
- Create a multi-channel track (e.g. 5.1)
- Insert mono or stereo plug-ins in pre-fader and post-fader slots (VSTII or III makes no difference, AFAICS)
- Open the routing window and move the plug-ins to any other channel than L / R
- Save the project, close it, re-open it
- Open the routing window again: Only pre-fader slots have kept their assigned position. Post-fader slots will all appear on L / R only.
… it’s a really pity that I won’t see a fix for this any time soon … :-/
BTW - I find it extremely confusing that there are selectable entrances for 5.1, individual channels and even 3D formats in the routing menu - but they can’t be selected.