Click the social icons on the item you want to tweak. If the icon is greyed out, that indicates that Beatrix won't post that item to that channel. This way you can share different content to different channels.
The two most likely explanations are: 1) Please ensure that you have given Beatrix the necessary permissions to post to your Facebook timeline. 2) Deleting / reordering items too near a scheduled posting time will sometimes result in Beatrix skipping over that time slot and resuming at the next scheduled posting time.
Beatrix is designed to manage your social accounts in a way similar to a human being. For that reason we prevent "high volume" posting as it does not seem natural. The sweet spot for businesses on social media is around 4 posts per day, according to various studies (which you can google!). Capping Beatrix to 4 posts per day means Beatrix can do her job without overwhelming your audience.