I am working with iOS6 and Xcode 4.5, I am getting an UI issue with some UIButton, some of the buttons title are not getting shown in my view.
In an older version of iOS everything works as expected.
Please see the following image. It’s not showing the text “Button” while executing it on simulator

I had a similar case which I just resolved. I think I know what triggers the issue with auto-layout.
I assume that you have created one button, then copied across the row and then copied the rows down. When you do that, one of the auto-layout constraints that’s set is “Baseline alignment” between the buttons.
The problem is if this constraints (it does not have to be user-level) remains between buttons which are not on the same horizontal position, meaning between buttons in different rows. So select the problematic button and check to see if you have this constraint. This was my case:
If you do, select it, upgrade to user-defined and delete it. All magically works afterwards.