/content/update/:id isn't updating "alias" field

...but it should :)

I'm used to the fact, that the alias is "updating" while saving, when the alias string is deleted (in backend editor).

To use Joomla's own url safe string function (instead of making our own) I added this line in ./plugins/services/joomla/joomla/content.php (around line 440)

if(!$app->request->params('alias') && $app->request->params('title')){
$article->alias = JFilterOutput::stringURLSafe($app->request->params('title'));
}

It says "If "alias" is not given but "title" is, convert the title into a url safe string and puit it into alias field. Works good for me and is closer to Joomla's behaviour.