Selecting same child with different parents creates two entries

I have a hierarchical list for wine awards, with a parent year and the children as wine awards. As an excerpt:

2005
- All-Canadian Wine Championships
- Canadian Wine Awards
2006
- All-Canadian Wine Championships
- Canadian Wine Awards

I'll select 2005, and then 'All-Canadian Wine Championships', and press the Add button. Great. Then, I'll select 2006, and then 'Canadian Wine Awards', press the Add button but then three entries are put into the selections table:

2005 › All-Canadian Wine Championships	 Remove
2005 › Canadian Wine Awards	 	 Remove
2006 › All-Canadian Wine Championships	 Remove
2006 › Canadian Wine Awards		 Remove

and end up being displayed on the node as:

2006
Canadian Wine Awards
All-Canadian Wine Championships
2005

There are a number of issues/questions I have:

1. Why is one choice accepted without a problem, but then the next select creates 3 entries?
2. When removing these items, multiples are deleted at once and the last entry is just the parent year. Why is that?
3. Why when viewing the saved node, there is a parent term and then its child, followed by a child and then its parent??

Please let me know if there is additional info you need. I've attached a small movie to illustrate what is happening. Thanks.