Manage questions doesn't work properly

I can add questions through the 'first page' of manage questions just fine.

When I use the filter options however, i can select the resulting questions that come up, but they won't be added to the quiz. Upon saving the Quiz node with some of these search results selected, questions that were already part of the quiz get truncated as well, resulting in an empty quiz.

I'm using the Alpha 12 build and the questions I'm trying to add are of the multichoice type (although I doubt that makes any difference).

Here's what I do:
=> Manage questions automatically returns a number of questions, I select a few of them and see them added to the quiz (unsaved, but if I save the quiz node it works fine)
=> I then filter on a certain title, and check those too (these don't get added)
=> I then save, and see my quiz node empty (regardless of how many questions were attached)