His story was different when Tesla was first banned. But then he wasn't running for national office.
That was 11 months ago. I'm pretty sure Chris Christie's political ambitions haven't radically altered in the meantime.
The original "ban" was a perfectly reasonable reading by a regulatory body of the existing law. Regulatory bodies shouldn't be in the business of rewriting unpopular laws; that's the legislature's job, which appears to be what happened here.