EDIT:
Using Version: 4.2.3.3 on windows XP and Win 8.1
It seems that there is an error (tried with two computers / installations of Impress), if you want to animate one long sentence to “scroll through”, which contains more than 60 characters
The behavior of the text animation “scroll through” is deferent if you includes “carriage returns” then the entire text block moves (in stead of scrolling in the text in one row)
Please watch this video which will illustrate the problem