Hi Dietz,
I suspect that the automatic Role selection, and the Apply Role Preset command is not working in MIR 3D.
I'm using the latest version, on a Mac Mojave. Hosted in VEP and in Dorico (VST).
The Role Preset clearly doesn't change when changing venue. And it doesn't change when pressing the button in the Preset Management window.
The only way to make the Role Preset be accepted is to drag it on the instrument line in the Preset Management window.
Paolo