Why is part of my text disappearing when I post an update in Activity Stream?

I’m having an issue where when I write into the Activity Stream text box and try to post it as a new update in the Activity Stream nearly all of what I wrote will disappear and only parts of it will be left. To get what I am trying to post in the Activity Stream to show up the right way I have to edit it and re-write everything, I’m using the Buddypress Edit Activity plugin for that.

Do you have any ideas what could be causing this problem when I am posting an update in the Activity Stream?