In Script configuration, Enable confirmation cheked and Test confirmation clicked.
Then, confirmation dialog is displayed.

But, that dialog header was encoded string with multibyte language.
ex. Japanase environment, header string is "\u5b9f\u884c\u306e\u8a8d".

I checked PHP source.
I think CJs::encodeJson is duplicated at line 16 on include/views/js/general.script.confirm.js.php

NG

title: <?php echo CJs::encodeJson(CJs::encodeJson(_('Execution confirmation'))); ?>,

OK

title: <?php echo CJs::encodeJson(_('Execution confirmation')); ?>,