I think we are on Moodle 3.82+. That is the version number I saw quoted by one of our Teaching Centre people when we were debugging something else earlier this summer. (As far as I can tell, faculty do not have sufficient privileges to view things like version number!)
Some of the difficulty is probably that I can't sit down in the same room as someone with admin privileges on Moodle to figure this out.
Of course we know other options for injecting a WeBWorK problem into a webpage (like in PreTeXt) but I don't know of a way to do that in a way that would result in an answer being recorded by a Moodle quiz question.
I had good intentions of learning how to use your script to generate Moodle question banks from WeBWorK set definition files. But the instructions mentioned the need to create a new question engine each time, which requires admin privileges on Moodle. Our Moodle people are overworked as it is so I don't think they'll be happy if I flood them with requests for new question engines.