I notice in the browser that normal AudioMulch devices with two words don't have a underscore while vst's do.
Can it be fixed?
There are no AudioMulch devices with spaces in the names. AudioMulch doesn't support names with spaces in them, so it substitutes underscores. There are various reasons for this related to supporting OSC and or scripting which may happen in the future. So it's unlikely it will change.