Group Posts Not in Group Theme if Content Type Also Used in Non-Organic Group Content

I'm setting up OG in a pre-existing site and am new to OG. I have two enabled themes--a theme I am using for just OG and a theme for the rest of the website. A content type not used elsewhere on the site posts in the chosen group node theme. All other content types post in the default theme instead of the group node theme. I've cleared all caches with drush option 1 and browser cache and cookies. Is there something I am doing wrong, not doing, or could this a bug? I'm using the basic OG dev module with OG statistics enabled on a 6.19 installation.