Graphic problem with UI Text

Hi! I have a strange problem with two UI Text in my scene.
Sometimes(not always but often) in the editor and on my tablet, the text appears “damaged”, as in the picture below.

I’m new with UI System and I don’t know why this happens and how to solve.

Normal image: http://i57.tinypic.com/11qtthy.png
Image with errors: http://oi60.tinypic.com/wcd75k.jpg

No idea from looking at the pictures. Can you notice any pattern as to when this occurs? Are you using any scripts? (looking at those might help)
Might want to make sure the text items are drawn ONTOP of other controls, by placing them at the top of the list in your canvas, in the editor.

Hi, try to change font. Some devices may not support the font you are using.