Yeah…I bet I know what happened.
Their plugin reports that they don’t use audio inputs but I bet they are not clearing the audio buffers so anything that happened to be in the buffers just got passed through.
We’ve seen this before from IK in one of their compressors where there was no MIDI input and they weren’t clearing the MIDI input buffers consequently MIDI CC messages coming into GP were being processed by that compressor even though there was no MIDI connection. We couldn’t get IK to pay attention and we ended up adding in a hack to our system to detect that plugin and clearing the buffers ourselves.
Please report this problem to IK and perhaps include a link to this discussion topic.