Occurs in Fiber with multiple instances of the React package (which can't share current owner).
returnFiber: Fiber,
    current: Fiber | null,
    textContent: string,
    priority: PriorityLevel,
  ) {
    if (current === null || current.tag !== HostText) {
      
      const created = createFiberFromText(
        textContent,
        returnFiber.internalContextTag,
        priority,
      );
      created.return = returnFiber;
      return created;
    } else {
      
      const existing = useFiber(current, priority);
      existing.pendingProps = textContent;
      existing.return = returnFiber;
      return existing;
    }
  }
  function updateElement(