Is this a potential symptom of a hardware issue? Button visual data is behaving buggy? Recently, I opened my Gmail application on my (brand new) iPhone 4S.  I've been using the phone for a couple of weeks, and I downloaded the Gmail application a couple of days ago.

As you can see from the image below, the buttons on the far right started to behave in a funny manner when I launched the application.  I hit the home button and opened the app again, and it still looked like the image below.  So, I double-tapped the home button, closed the app and re-opened Gmail and that fixed the buttons.

I could choose to ignore this is because it could be a one-off error or it could be a problem with Gmail.  However, I am also aware that this type of visual error can be caused by some form of hardware error.

Do I have anything to worry about, considering the nature of the error?  Should I take this image into an Apple store and have them service my phone?

I'd rather get this taken care of if there is something that can be done before to long, especially since my phone is so new.
If that doesn't happen in any other app, it's likely a bug in the Gmail app. You should raise this issue with Google's support.