This appears to be broken in two different ways:

• The secondary type of the RG is re-entered because the old type is incorrectly shown as empty.

E.g. http://musicbrainz.org/edit/31496584

• It does not check if any changes have been done to the release group after the "edit release" page is loaded.

1. Edit a release where the primary type of the RG is "none/unspecified".
2. Press the "Copy the release artist credit to the release group" button.
3. Go back to the release group in a different tab, set the primary type and enter the edit.
4. Go to the "edit note" tab on the release edit page, the changes are loaded, enter the edits.

Expected behaviour: The current info about the RG is loaded on the "edit note" tab and only the release artist credits are changed.
Actual behaviour: Primary type is removed and the release artist credits are changed.