My question have reputation +5. As it migrated from askubuntu to superuser, my superuser account gain +5 reputation but does not subtracted on my askubuntu account.
So now +5 on both account with same question.
Links to the reputation tab on both accounts are: askubuntu superuser
So isn't that the askubuntu reputation tab should show like
Migrations do not trigger reputation recalcs on their own - deletions do. Until the question actually gets deleted (which automatically occurs 30 days after the migration) then the reputation will not be lost on the source site.
Answers to migrated questions get deleted immediately upon migration, and you lose the reputation from those answers immediately as well.