After watching your video, it appears I was correct. The editor hasn't fully loaded when you begin typing. To avoid this issue in the future, you should wait till it's fully loaded before beginning to type your post.
Thank you for reporting this. I will pass it along to the tech team for investigation. If you could provide screenshots, I'll pass them along to the team. As the Tapatalk installation in use is a highly modified plug-in, Tapatalk integration does require a lot of work from the team. We would suggest using our mobile interface instead, as it was designed to be a better integration than Tapatalk.
If you can record this on your screen with VLC or Jing (http://www.techsmith.com/jing.html) so the tech team can watch it, it would be appreciated. It sounds, however, like the editor isn't fully loaded when you're starting to type.
A video, however, would help us confirm this.
What browser and OS are you using? I'd like to see if I can re-create this issue.