Crash get_header();in index.php

Focus crashed serveral times. The error log showed
1. unexpected T_ECHO in attachement.php on line 19
2. PHP Fatal error: Call to undefined function get_header() 
Fixed the first error by replacing line 19 by:
 esc_html( get_the_date() )
Fixed the seccond error by replacing:
get_header();
by
<? if (function_exists(‘get_header’))
{
get_header();
}
else{
exit;
}
?>
Something for the next release, or is something else wrong?