Multiple choice field with choices from shared field - wrong choices

I have a multiple choice field in one table that shares the selection options from a field in a different table. Instead of pulling from the typed in list of possible selections, it pulls from the field data itself. So any selection that has not yet been made will not appear. 

In my case, the source list is where defaults will be set, so some values will never be used in that table, but I need the values to appear in the second table where these defaults can be overridden.  

I can work around by manually duplicating the list in each multiple choice field, but this seems like the wrong answer.

I understand why it may have been done this way, but it is lousy for my use case.