This sounds suspiciously like the conflict that happens sometimes when tag taxonomies, custom post types, and menus collide in a weird way. I have only found hacks for this issue, and many of them are listed in this thread on WordPress.org.
This sounds suspiciously like the conflict that happens sometimes when tag taxonomies, custom post types, and menus collide in a weird way. I have only found hacks for this issue, and many of them are listed in this thread on WordPress.org.