Being assigned an office doesn't mean that it's not remote. It entirely depends on the team. I worked for a team that wanted me in office for three days a week last year. My current team is entirely remote, but I'm still assigned to an office that I can go to anytime I want, which is totally optional.
On the other hand, I had exactly this sort of issue with Amazon subsidiary Zoox a couple months ago. We had verbally agreed on terms that would have me doing primarily remote work. When they finally sent me terms, they specified full time in-office and changed a few other things like salary. The excuse was that some higher-up wouldn't approve remote right now, but they were trying to convince them.
No, but here's the catch that I learned about: if you're assigned to an office, they can make you go into that office at the same frequency as in-office workers. You'd basically have nothing in writing that states you're a remote employee (I specifically asked the recruiter about this, and he confirmed). Otherwise why would being fully remote need "special approval"? That doesn't make any sense.
