If you record a MIDI track take and then use Edit>Undo Tracks MIDI Recording, all VST presets configured are emptied and you will suddenly be getting no sound. This is happening for at least the last two VSL versions. Since I’ve imported a large MIDI file to begin with, that’s a lot of presets.
If you immediately use Redo MIDI Tracks Recording, the presets are re-populated.
If I don’t like a take, I’m just doing what I did in Cubase. I can’t think of a reason to wipe all VST presets in this context. If you don’t think to use Redo, then you have to choose between losing all unsaved takes for the session, or having to re-configure all presets.
The work-around is to use the Erase task from the toolbar to erase the unwanted take, and perhpas saving the project between each take to feel safe.