The ReMOTE SL has three virtual MIDI connections or 'ports' over USB. These appear as port 1, port 2 and port 3 on your computer and are labelled USBa, USBb and USBc (or Ua, Ub and Uc for short) on the unit. Port 1 is used for all non-Automap data, including keyboard, pitch, mod etc. Port 2 is used for mixer Automap data i.e. data used to control the program/application itself. Port 3 is used for plug-in Automap data.
For the HUI templates, the keyboard and joystick are set to transmit on port 1 as they are not part of the Automap. All other controls send on port 2. Additionally, the SL sends constant C-2 note-on messages to DP and DP sends constant C-2 note-off messages back to the SL, both on port 2. These messages are used to establish the connection between the SL and DP so that if either device stops receiving these messages they know that the connection is broken.
You need to make sure that any MIDI or instrument tracks in DP are not set to record MIDI data from ports 2 or 3, only port 1, such that you do not record automap data or the C-2 handshaking messages. To allow tracks in DP to receive MIDI data from specific input ports you need to set up multi record. The following is taken from the DP help file:
Choosing a Multi Record input source
When Multi Record mode (in the Studio menu) is turned off (unchecked), a record-enabled MIDI track will record data from any MIDI channel.
When Multi Record mode is turned on (checked), each MIDI track can record from an individual MIDI device on a particular MIDI channel. This lets you record into several independent tracks from several independent sources during a single record pass. Each MIDI track displays its own incoming MIDI device and channel number next to its record-enable button. These device-specific recording assignments are only present for MIDI tracks in Multi Record mode.
Click on the current input source to change it. If the input assignment for a MIDI track is blank, click in the blank space to open a menu of MIDI devices. You can select only one device and channel for each MIDI track. If a device menu does not appear when you click on the blank space for a MIDI track, make sure that Multi Record is checked.