The idea that if you copy a quiz more than once - that the original should then be deleted - is asinine.

I'm copying it more than once because it's important and I need several versions.

For reference, I create a practice test (version one), then modify slightly to create an actual test (version two), then create a third version (WOOPS! Silly me right?!) for students with accommodations for their actual exam and then BAM - right in the middle of studying in crunch time - students' practice tests disappear. 

Try to fix that and WHAM! The actual test disappears. This is madness of the highest order.

Vague language about "importing" (note: not copying) content more than once is insufficient.

I have wasted literally tens of hours, multiple days, under high-pressure deadlines with hundreds of students, trying to fix the mayhem caused by this function.