Hello WWandC,
Contrary to Todd's comment, we do provide support: Monday - Friday, however we do not reply to direct requests for Support assistance.
If you would like Rapid Response Support, we will respond to your questions within 24hrs, no matter what day you post your question.
In answer to your question: We would need a link to the site that is having an issue displaying both videos, as well as please ensure that TubePress Debug option is checked. The most likely causes, however, are that the video is geographically restricted to not be playable in the region/country that your hosting providers server(s) are located, the video is marked as un-embeddable, or the YouTube API just simply hasn't updated yet, which we have seen take up to 96 hours to fully update. That just depends on how busy YouTube users were adding new videos.
Please post a link to your site where you are experiencing the issue and we will be more than happy to take a look.
Thanks!