Embedded complex widget remembers previous value

Setup:
Have 3 content types: page, article and block (names unimportant obviously)

Add a related articles field (unlimited) to the page content type with the ief complex widget (add new only)
Add a related blocks field (unlimited) to the article content type with the ief complex widget (add new or existing)

Go to /node/add/page and then create the first related article with a related block. When you try to add the second related article, the related block field will be pre-populated with the related block that you associated with the first article.

I've checked and this only seems to be an issue with the complex widget. If you were to save the page node after adding the first article with related then add the second article in the page edit screen then the related block field would not be pre-populated. But if you were to add a third related article without saving the page then it will be pre-populated with the value of the related block from the previously added article.