**Do you want to request a *feature* or report a *bug*?**
bug

**What is the current behavior?**
If there is a client/server mismatch for text inside of an a or button element, it causes it to be automatically focused on page load.

**If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem via https://jsfiddle.net or similar (template for React 16: https://jsfiddle.net/Luktwrdm/, template for React 15: https://jsfiddle.net/hmbg7e9w/).**
```
let text;
let URL = '/randomURL';
if (typeof window !== 'undefined') {
  text = 'CLIENT TEXT';
} else {
  text = 'TEXT';
}

return (
  <a href={URL}>
    {text}
  </a>
);
```

if the focus is not on the window (i.e. if a dom element is selected in the chrome inspector or react inspector widnow), then it doesn't add the focus.

**What is the expected behavior?**
The expected behavior is that it would either show CLIENT TEXT or TEXT (depending on how React16 resolves the diff), but for it not to be automatically highlighted 

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**
React16 / macosx / chrome + ff + safari
ReactControlledComponent,
    ReactDOMComponentTree,
    ReactDOMEventListener,
  },
};
if (__DEV__) {
  
  
  
  EventPluginRegistry.enableWarningOnInjection();
}
type RootOptions = {
  hydrate?: boolean,
};
if (enableCreateRoot) {
  ReactDOM.createRoot = function createRoot(
    container: DOMContainer,
    options?: RootOptions,
  ): ReactRoot {
    const hydrate = options != null && options.hydrate === true;
    return new ReactRoot(container, true, hydrate);
  };
}
const foundDevTools = DOMRenderer.injectIntoDevTools({
  findFiberByHostInstance: ReactDOMComponentTree.getClosestInstanceFromNode,
  bundleType: __DEV__ ? 1 : 0,
  version: ReactVersion,
  rendererPackageName: 'react-dom',
});
if (__DEV__) {