I had previously written before about a problem with instruments and my gl code. Since it was too vague a question/issue, I decided to try and hunt down the problem. I found that the call below was crashing the iOS app only when running instruments. This was NOT the case before the latest IOS and OS X update. Removing the line makes everything work again.
I did not test to see if the problem is the debug.writeline on it's own or if it's the GL call within the debug that causes the issue.