I just recently jailbroke my iPhone 3GS on 4.3.1. I was having this problem before I upgraded and re-jailbroke and it was fixed temporarily and then just came back today, here's the problem:
When receiving a text message my phone does the normal noise/double-vibrate, but the screen will not display the text until about 3-4 seconds after the audible alert. It's rather annoying...I thought it might be from Backgrounder, but after removing that it still exists.
Anyone else have this problem or any solution ideas?