A few things could cause this:

1. In your MIDI setup (FreeMIDI or Audio MIDI), make sure that the "Main" Mackie Control unit is connected to Midi port ahead of Expander(s); e.g. MackieControl=midi port 1, Expander=midi port 2.

2. In DP's Control Surface setup, make sure both "Units" are selected within one "Driver" selection of the Mackie Control. Set the "main" Mackie Control as the first "Unit", and expanders as secondary Units.

3. Makie sure the Mackie Control is not in HUI emulation mode, by holding the first two select keys (channel 1 & 2) while powering up the unit. On power up, the display will allow you to choose between "Mackie Control" or HUI. push the V-Pot below Mackie Control