The text editor for any kind of forum/pm/welcome message input has a mind of it's own, I've had this issue for weeks now.
Here is how the first automated PM gets sent out to new members who have registered - http://prntscr.com/71yde6
This is how it's been saved in the editor via Membership and Registration - http://prntscr.com/71ygux
This is how I WANT it to look - http://prntscr.com/71yfcj
Personally I've given up and just laugh, I call it a feature not a bug.
All jokes aside I know iClan try their best bless em.