In the quiz for this section there is a question that asks what a Vector3 is made up out of. There are two identical answers in this question where one of those is the correct answer. This is highly confusing for any quiz taker as there is no way to distinguish them.
Quiz 36: Which is the correct way to create a 3D vector?
The four answers are all subtly different. Only one of them is correct. The other three will produce compile errors if used as an expression. (it’s not syntax errors, so nothing to do with semicolons, etc.)
Yeah I was going to pop a screenshot up of that, with a red box around the length of the answers, but I wasn’t sure if that was the specific quiz in question.
In fact, here it is… still have it open on my desktop! 
Strange, the answers I was shown were displayed differently. Could it be because of safari?
Now that I look back at the question it does display like the screenshot, I swear it was different before though, sorry for the false flag.