Strangeness when having more than one Modulation object in the layout

I get strange behavior on the modulation wheel shelf control when using more than one midi channel.

Example:

- Start Mainstage.
- Open a blank project, like Keyboard starter.
- Drag two mod/pitch wheel objects to the layout. "Learn" them to respond to modulation wheel (Midi CC#1) on midichannel 1 and 2 respectively.
- Make sure Midi Thru is set to automatic [1].
- Now check that it works. Sending modulation wheel on midi channel 1 will move one of the wheels, sending on midi channel two will move the other one. Fine.
- Go to Edit mode; very strange if I send modulation on channel 1 both will move. In some cases the other way round.

I get similar behavior on other midi CC's (like expression, CC#11) that are sent through directly to the plugins. That is, those that are marked "Same as input" in the parameter mapping.

Adding more channels makes it even more confusing. Mostly at least two of the modulation wheels will move although I'm only sending on one channel.

In layout mode all works the way one would expect.

I know these controls aren't really needed they are merely a visual yet helpful aid but why this strange behavior? Is it a bug or a feature I don't understand?

----------footnote:
[1] This is the normal way to set things up. The modulation wheel object is not assigned to anything it just sends through CC#1 to the plugin instrument.