While  working on my first quiz for a Spring course at Harvard Extension, I was using a quiz bank with about 50 questions, most of which I've used before.  When I tried previewing the quiz, roughly a fifth of the items turned up with the wrong answer scored as correct. Somehow the answer keys had changed.

These are familiar items for which I know the right answers, so I didn't change them myself.  Many are items I’ve used for years without problems.  (A little history, in case it matters:  some of these items go back a decade or more, and were originally used in  Blackboard at another university.  They were moved at that university from Blackboard to Canvas, and then brought over to Canvas at Harvard.  But I've been teaching here since Fall of 2019, and didn't see this problem before.)

I went through the entire bank to fix what didn’t used to be broken, That seemed to fix all but one item, a simple T/F item.  I would correct it and then it would flip on me, as if Canvas was sure I had the wrong answer.  (For the record, here’s the item:  "In the doll-painting case, letting the blue-collar workers control the speed of the belt produced a predictable loss of speed and efficiency."  The correct answer is False). 

After this happened multiple times, I deleted the item and typed it back in manually.  I previewed the quiz, several times (because it draws items randomly from the full pool), and it seemed to be fixed. 

Except it wasn’t.  When the quiz went live, many students (but not all) were dinged because Canvas had changed its mind again and decided that the wrong answer was correct: as if Canvas is wedded to a management theory that giving workers control over anything is bound to produce bad results.  Fortunately, the problem occurred only for that specific item, but that was more than enough to produce significant distress among my students.   It isn't helping me achieve my hope that students will see me as a competent professional who won't preside over stupid stuff.

I can't come up with any explanation for how this happens.  If I hadn’t seen it myself over and over, I’d be skeptical that it’s even possible.  I asked Harvard instructional support, and they say they haven't seen this; they suggested I post here.  Is it only me, or have other users run into this issue?  Does anyone have an idea about how this could happen?