When you add a value with a space to your multipicklist and render it as checkboxes, the following happens:
The first word will be the for attribute of the checkbox label, with the rest of the String it does something weird.
Question
Multipicklist rendered as checkboxes, causes problem when there are spaces in the value

Translate
Reply
Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.