Logic Pro Weird Smart Controls mapping issue

There is some problem with the template that I have created (spent weeks creating!) The problem is that when I map smart controls to my external midi controller, it 'learns' the control, but then it won't actually move/control the mapped fader/knob.

Now, note that I can do this in an empty template, it works fine, but then in the template I have created, there is something in it which prevents this from working.

I have tried disconnecting any fancy midi cabling in the environment before the sequencer input, but without success.

I follow the instructions in the manual:

Assign an external hardware control using the Learn button
1. In the Smart Controls pane, click the Inspector button in the Smart Controls menu bar.
2. Select a screen control.
3. Click the External Assignment disclosure triangle.
4. Click the Learn button.
5. On your MIDI device, move the control you want to assign.
6. While the Learn process is active, you can learn additional controller assignments by selecting another screen control and moving the hardware control you want to assign to it.
7. When you're finished assigning controls, click the Learn button again to end the Learn process.

Now, I do this, but and it has clearly learned my assignment as it shows this in the box there - but when I move the controller - it does NOT move the 'smart' control on screen.

Can anybody think WHAT this could be in the template which is preventing this from working?

I would appreciate any help.