Only one instance showing in Bitwig Studio

1. The Problem

Oszillos Mega Scope or Spectrum 2 plug-in instances do not find each other in Bitwig.

2. The Explaination

Bitwig Studio implements plug-in isolation. This means that plug-ins are run in separate processes. This is actually a pretty neat technology because when a plug-in crashes your DAW keeps running and you're not loosing any data. Unfortunately this prevents the plug-in instances to find each other.

3. The Solution

Set the "Plug-In hosting mode" to "By manufacturer" in Settings / Plug-Ins:

BitWig Studio Plug-In isolation settings.