Problems with multiple menuitems referencing same node

I have several problems with menu items that all reference the same node. When scanning the issues, I found out that others also have had similar problems. I have installed and activated Pathauto 5.x-2.0, Path 5.5 and Path Redirect 5.x-1.x-dev.
Example Menu structure without Path activated:
Primary links
- Item PL1 -> node/4
Secondary links
- Item SL1 -> node/6
Navigation
- Item NV1 -> node/4
-- Item NV1.1 -> node/6
- Item NV2 -> node/4
-- Item NV2.1 -> node/6
Legend
Menu item display name -> pointing to node
Problems

• If you click on "Item PL1" or "Item NV1" or "Item NV2", the node/4 will be displayed, but the menu for "Item NV1" will not be expanded nor for "Item NV2"
• If you click on "Item SL1", the node/6 will be displayed, but the menu for "Item NV1" will also not be expanded nor for "NV2"
• If Item SL1 was not pointing to node/6 (i.e. node/6 is only pointed to by "Item NV1.1") a click on "Item NV1" would expand NV1 and ItemNV1.1 would become visible and clickable.

What I expected drupal to do:

• Click menu item referencing node/4: expand "Item NV1" and "Item NV2" and display node/4
• Click menu Item referencing node/6: dito, display node/6

Example Menu structure with Path activated:
Primary links
- Item PL1 -> nv1 (-> node/4)
Secondary links
- Item SL1 -> nv1/nv11 (-> node/6)
Navigation
- Item NV1 -> nv1 (-> node/4)
-- Item NV1.1 -> nv1/nv11 (-> node/6)
- Item NV2 -> nv2 (-> node/4)
-- Item NV2.1 -> nv2/nv21 (-> node/6)
Legend
Menu item display name -> pointing to URL-Alias (-> alias for node)
Problems
currently the same as above though I was expecting the following:

• If you click on "Item PL1": "Item NV1" gets expanded because it uses the same URL-Alias, displaying node/4. Item NV2 gets not expanded, because of the different URL-Alias!
• If you click on "Item SL1": "Item NV1" gets expanded because it contains "Item NV1.1" which uses the same URL-alias as "Item SL1", displaying node/6. "Item NV2" gets not expanded because of the different URL-Alias in NV2.1!
• If you click on "Item NV2", only this item gets expanded, displaying node/4
• If you click on "Item NV2.1", only "Item NV2" gets expanded and node/6 will be displayed

Of course the corresponding classes should be assigned to all nodes using the same URL-Aliases!

If you first assign the URL-Alias to the menu item and then define the URL-Alias, it may work. But if you edit any URL-Alias that point to the same node, it will fail then!

I'm confused, but I think Path redirect will help (with additional overhead!)