When I form a matrix-ranking question, deploy the form, and then open it again for editing, the entire form is not functioning anymore after redeploying it. After redeploying the matrix-ranking question can't be passed, and a pop-up says "answering is required" while all of the questions are ticked.
The awkward thing is that the matrix-ranking question seems to stops working only after at least one form has been filled in and sent back to the server. If you open the form for editing after this has been done, the sub-questions of the matrix are presented differently than before. It happens also if you leave the matrix-ranking question in-tact, but for instance add another question to the form.
This makes testing the (beta) question type 'matrix-ranking' almost impossible.