Steps:

1. Create a measurement attribute with a specific unit e.g. Weight in kg
2. Create a product type and product with this attribute.
3. Go back to Attributes and edit this attribute
4. The value defined before in Base unit is not displayed

1. Click select in Base unit, wrong units are displayed for the selected type.

1. Remark: should it be possible to modify the base unit and type, if this attribute is already in use?