1. Create a custom BBCode (i.e. [br][/br]) that renders to <br />
2. Create/edit one poll option using that BBCode
3. Preview the poll (with its option)
You'll see it renders as two options instead of one option. The culprit is in \posting.php:
The last line wrongly assumes <br /> is a unique translation of "\n", but that is not true anymore once a BBCode translates to <br /> aswell, leading to cut one poll option into multiple.
A more than obvious fix is to parse each poll option on it's own by simply replacing the code above with: