If the clock source of your Modal device is set to 'auto' or 'external' and the tempo of the device appears to be double what it should be when using MODALplugin, it is because clock messages are being sent to the device by both MODALplugin and the host DAW simultaneously.
To resolve this, either disable the 'Sync to Host - Clock' control in MODALplugin (top bar on the UI), or disable the DAW from sending MIDI clock / sync messages to the device. Please don't enable both at the same time.