Changing alias in node edit does not seem to work correct

I changed the alias pattern for the blog content type, but I ran into some problems while adding new aliases to the existing nodes.

These are the tests I did:

Test 1:
- Click Edit on node
- Leave Automatic alias unticked
- Save

Result: No new alias is generated.

Test 2:
- Click Edit on node
- Tick Automatic alias
- Save

Result: New alias created, but old alias remains in URL alias field in the node.

Test 3:
- Click Edit on node
- Tick Automatic alias and remove existing URL alias
- Save

Result: Same as Test 2

Test 4:
- Click Edit on node
- Leave Automatic alias unticked and remove existing URL alias
- Save

Result: The alias that was in URL alias is now removed. Other aliases for that node still remains in the URL alias list and URL alias in node edit shows it.

In all tests above I used "Create a new alias. Leave the existing alias functioning." in the Settings tab.