portfolio-view class missing from body in template

The body classes are filtered to apply the “portfolio-view” class where it’s needed:
https://github.com/devinsays/portfolio-press/blob/master/extensions/portfolio-helpers.php#L57

If you’re creating a custom page template and also need that class applied, you’ll have to add it with a custom body_class filter also.

So if I understand you correctly, I have to make a custom body_class function? Do I insert this function in functions.php or somewhere else? Thanks.

If you’re using a child theme, functions.php would be the place. If you are editing the theme directly (i.e. not planning to update) you could just edit the existing function that adds body classes.