When entering a custom prefix for InfluxDB that includes a dash the plugin is incorrectly substituting the dash for an underscore. This isn't necessary and is confusing if you're using the prefix to query the data.  The AbstractPointGenerator is incorrectly passing the custom prefix to the measurementName() method. This isn't necessary, it's not being used in the measurement name but rather in the Prefix tag.  Tag values can have underscore.