I think you're spot on in your diagnosis. Because of the way data are managed for gateways, the test versions that students take have a lot of saved information about the test, which results in things like the IP restrictions not being inherited as one might expect. I've been reducing the amount of information that is saved for the set versions to reduce that, but I don't recall if that is in the patches or unstable source tree.
WeBWorK Main Forum
Print/view old gateway quizzes from outside IP area
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