Different sorting results find() vs. sort() - why?

[titanium]

Given three pages with the following titles:

• Deutschland
• Österreich
• Schweiz

I noticed that I get different results for a sort inside a selector and an explicit sort(). See the following example: 

// A) just use selector as usual
$countries = $pages->find('parent=countries,sort=title');
foreach($countries as $country) {
	echo $country->title . "\n";
}
// result: Deutschland, Österreich, Schweiz - ok

// B) put pages in separate array and sort afterwards
$countries = $pages->find('parent=countries');
$whitelist = new PageArray;
foreach($countries as $country) {
	$whitelist->add($country);
}
$whitelist->sort('title');
foreach($whitelist as $country) {
	echo $country->title . "\n";
}
// result: Deutschland, Schweiz, Österreich - huh?

It seems to be obvious that it has something to do with the umlaut in Österreich. Maybe a bug?

[FrancisChung]

Maybe this could be of use?

https://processwire.com/talk/topic/12776-pw-3012-support-for-extended-utf8-page-namesurls/

[kongondo]

I have not checked their inner workings, but the sort in A is done at the database level (SQL) whilst the sort in B is done at an in-memoy level (PHP). Maybe this difference has a bearing on the sorted results.