Charging W-2 employee rent?

Hello all, I'm an associate licensed counselor in the US who is very close to full licensure. In talking with my supervisor today, we were discussing some next steps in my employment with her once I'm fully licensed and begin the insurance credentialing process.

I plan to stay working for her as a W-2 employee for at least a year while I get credentialed and start out being fully licensed. It's a small private practice with one fully licensed clinician (my boss/supervisor/owner) and a few supervisees. Our boss rents a few office spaces for us to work in and it's been a really good experience so far.

When talking about expectations after I'm fully licensed, my supervisor mentioned she would start charging me rent for the office space I use. I was a little confused by this since I wasn't expecting it, but it seemed reasonable at the time. I'll be getting a raise and everything, so I thought, yeah, it makes sense to start paying rent.

After thinking about it for a while though, I'm uncertain. Is this standard practice? I've read conflicting information about group practices and what to expect as a fully licensed clinician. I've also read it's illegal to charge a W-2 employee rent?

I believe my supervisor to be a good employer, and I don't think this is being done out of greed or maliciousness. She's never had a clinician stay employed with her after getting fully licensed, so we're all kind of flying blind here a bit and figuring things out as we go.

Any insight would be appreciated.