I've found that in the drag and drop text content type, the last letter doesn't appear in the exercise. You can read read more here.
Mon, 03/16/2015 - 11:18
Fri, 05/08/2015 - 10:21
Sorry for taking so long to get back to you, hopefully you have already updated drag and drop text to fix this.
The issue was fixed in this commit at github, and will be automatically fixed by updating to the latest drag and drop text from h5p.org.
Connect with H5P
H5P is a registered trademark of Joubel