[room500]

But it is acting as if it wasn't a mutual agreement.

Maybe "resignation" doesn't meet your criteria. But "firing" implied that the employee wanted to keep their job but the company ended it.

Would you accept "mutual termination" ?

[pseudalopex]

It wasn't a mutual agreement. She wanted to keep her job until she was back from vacation at least.[1]

[1] https://twitter.com/timnitgebru/status/1334341991795142667

[refurb]

So she was fired after making demands the employer wasn’t prepared to meet, including keeping her employed until after her vacation.