HR Diva here:

First, the plan is administered by Schwab.
The plan sponsor doesn't have to remove their unvested match from your account until you decide to move your account. You are always 100% vested in your own contributions.
They will remove it at some point. Sometimes it just happens when they get around to it. Sometimes it is when they change administrators (ie: Fidelity to T Rowe Price to Schwab). Sometimes they wait till you want to transfer it out. It doesn't matter. It's not your money and they know it.
Spirit doesn't get it back; it goes into a forfeiture account. They can use it for plan expenses, but it never goes back to Spirit as general assets.

I hope this answers your question and stops the wild speculation!

Kind regards,

HR Diva