Okay, this is working in the previous asset store release of NGUI, but has broken in the latest release.
I have a sprite which is just a green circle which is used as a vertical progress meter. I have another script which keeps its value in sync with the game state.
When the game first starts the meter becomes squashed, and remains squashed for the duration of the game. During play mode, if I delete the widget and then select Edit|Undo it corrects itself.
If I remove "mySlider.value = healthPercentage;" from within the "Update" function of my script it also behaves. The problem only seems to occur when the game first instantiates the GUI from a prefab. If I begin the game with my update script disabled, and then enabled it in-game, the widget renders properly.
Here is a screenshot:
http://pbrd.co/IRCFMlThe widget on the left is how it incorrectly looks upon starting the game. The widget on the right is how it should look.
If the widget on the left is duplicated (Ctrl+D) during play mode, it appears properly (the one on the right is a clone).