Since it is not possible (or rather difficult) for Windows to access a connected hardware in several places, you could try deselecting the Blofeld in the DAW device manager. This way the plugin can communicate with the hardware as the DAW itself does not use the USB port. Otherwise you have the problem that the Blofeld hardware is recognized in the plugin but cannot be selected.

Alternatively, you could try connecting your Blofeld via USB only when the DAW has already been started and you have already opened the Blofeld plugin.

Similar behavior has been described by other users who work with various DAWs on Windows.