CSV File Import - adding a project is broken due to JS error

1. Go to CSV import
2. Choose a CSV Source File, click Next
3. A JS error is thrown on the Set up project mappings page:
   Uncaught TypeError: Object [object Object] has no method 'appendOptionsFromJSON'

1. Click edit to add a new project.
2. Enter project details, click Add
3. Same error is shown, dialog is not closed, Add button is disabled and the project is not added.

This is both in OnDemand and BTF.