I don’t think I’m using any form of template modification here. I’m only using the following modified templates sitewide.

wp-content/themes/theme_name/
├── buddypress
│   └── members
│       ├── index-register.php
│       └── single
│           └── home.php
├── footer.php
├── mediapress
│   └── default
│       ├── buddypress
│       │   └── activity
│       │       └── views
│       │           └── grid-photo.php
│       └── shortcodes
│           └── grid-photo.php

I’ll take a look at the code and see if there’s a reason the post_id might be modified from somewhere…