"Undefined" result for something that used to work

Something’s not working the way it seems like it should.

When I … input the correct answer

I saw … (undefined, undefined)

But I expected … “Great job”

Here’s the link to the page, dashboard, or activity: [SOE] Introduction to Graphing Systems of Equations • Activity Builder by Desmos
Slides 5-7
Note: This is an edited version of the activity, but the original has the same issue. It used to work great (last spring.) Also, I did email the author as well but thought I’d try this board too.

And here are some screenshots or a video:

Thank you!!

Hey Elizabeth!

This isn’t so much a bug in the system as it is a (possibly very minor) error in the way the activity is coded. Changing the category over to questions so that folks can weigh in with their ideas.

It’s the brackets in the code that are causing the problem:

Remove them (and the extra variable definition if you like)
or just

(Similarly, both of the following work)
number("x_5"): numericValue("${T1.x}")
number("x_5"): numericValue(T1.x)

Question for Jay et al.: if it was working last spring but now isn’t, has something changed in the code rendering (or whatever it’s called – I’m a hack coder and don’t know the proper vocab) that would cause this problem? I wonder how many activities have potential errors like this – you won’t know there’s a problem until you use it with a class.

Nothings changed in the system that would have previously allowed this to work. My best guess here is that the activity was slightly edited or that the recollection of how it worked last year is slightly different from reality. E.g. entering the coordinate pairs as just comma separated values (without the parentheses) still works.