It's a bug. From Andrey's post, it sounded like trying to submit a long list, results in an sql query that is too long, and MySQL chokes on it. If I interpreted what he said correctly, then saving the list should be broken up inot several smaller queries.
I added the list of 50 states manually, and they all show up fine in admin. I've noticed that in the forms that the list is used on, the list is also truncated. Sounds like a problem getting long lists in and out of the DB, and it needs to be fixed.
http://www.boonex.com/trac/dolphin/ticket/1605
My opinions expressed on this site, in no way represent those of Boonex or Boonex employees.