Incorrect "Too many variables in head of rule"

In this specification IDP-Z3 complains about having too many variables in the head of the rule. Make_and_Model_is_in_all_Groups expects a Make and Model argument, which are given via Car and two functions. My guess is that IDP-Z3 doesn't like the usage of Car, and instead wants quantification over makes and models? In IDP3 this was no issue however.