It is easy to think of a way to make free angular momentum from an actual magnetic monopole. Who can do this without searching the internet? Why do academics not do basic plausibility checks on their work?
And no, quantum mechanics is not exempt from conservation laws in ways that are macroscopically measurable. The Bianchi identities prohibit this where the metric exists. There was a failure to detect any slowing of gamma rays across the universe by vacuum effects.