A Geogebra problem is showing blank coordinate system without the graph of the function that should be manipulated. This happened only for one student and only after he tried to reset it.
It is Contrib/CUNY/CityTech/Precalculus/setTrigonometry_-_Graphing_Comprehensive/per-phase-cosine.pg with random seed 997.
Even if I change his random seed and he gets a different question, the graph stays blank. Using the same random seed for myself I cannot recreate the problem.
This is a problem I wrote, and have seen this error pop up occasionally in our courses as well. The fix is to change line 259 from reinitialize_button => 0 to reinitialize_button => 1
What happened was that the student submitted a response prior to the applet being fully loaded. In such a case, the past answer table no longer contains any state for the applet, and as a result, the applet is loaded without any contents. By enabling the reinitialize button, you may reset the state of the applet on behalf of the student (or they may do it for themselves).
While I don't see this issue pop up very often, it is perhaps worth making the change across the board on these Geogebra problems (there are several in Contrib/CUNY/CityTech/Precalculus/, all of which are susceptible to this issue).
This is not hard to replicate and is not dependent on the seed. Unfortunately this is not a new issue. I have known of this for a while. It is a limitation of the way we handle state for Geogebra applets that conflicts with the way that Geogebra applets themselves handle state.
To replicate this, make a change in the Geogebra applet and submit and answer. Then try the reset button. You will get the blank graph. If you now submit that, then you are stuck with a blank graph even when the problem is reloaded.
Apologies if this is a silly question, but did you make use of the reset button that now should appear underneath the applet? Just enabling the button would not be enough.