JsonUtility.ToJson claims it is thread safe, but it is actually not?

When trying to call JsonUtility.ToJson from a background thread (new thread(), isBackground = true) I’m getting the error in the console: Assertion failed on expression: ‘CurrentThreadIsMainThread()’

“This method can be called from background threads. You should not alter the object that you pass to this function while it is still executing.”

Are the docs wrong?

It isn’t , they need to fix this doc as it is misleading.