Can Custom Metadata be mass inserted?

My Custom Metadata Type is listed as a custom object in the Data Import Wizard but when I -

1. select the object
2. add new records
3. choose the CSV file
4. next

none of the fields are mapped and when I click Map an error's displayed

> 
> Something has gone wrong. Cannot read property 'length' of undefined.
>  Please try again.
> 
> 
> 

The Metadata Type is listed in Workbench for SOQL queries but not when I try to use it's insert function. It's not listed in the list of Dataloader objects.