PHP Shortcode Breaks other Shortcodes

PHP Shortcode seriously breaks the content passed to other spanning shortcodes (e.g., [some_code]content[/some_code]. The content is almost, but not quite a valid string. String functions like strpos for substr fail to return correct results on the string processed by PHP Shortcode. This is true even if you don’t have any code within the content that use PHP Shortcode.