Maybe everyone can access Muthur, much like one computer e.g. with win 7/10, everyone might have an account and different logins, but there's only usually 1 device administrator for it.
Either that, or Muthur needing to be rebooted and taking on a different default voice seem to be the only possibilities in which Weaver could voice now that we know another actress is involved. Its not very likely, but at least logically thosr could be the only scenarios.