incorrect hreflang

Hi,

I’m facing the problem even I already set “Locale at front-end” to zh-hk, in front-end still appear in “hk”.

Screenshot 1: http://upload.tennyy.com/upload/131470724732.png

Screenshot 2: http://upload.tennyy.com/upload/271470724744.png

https://ww.wp.xz.cn/plugins/qtranslate-x/