CoreGraphics printing weird message

I recently came to following debug messag, when I diplay some PDF files.

I think it occurs on some pages, when the CALayer redraws them.

Text clipping 0xab9b930:
 Node 0: XIXHYA+LinotypeFeltpen-Medium-OV-IFXHYA (31.0031, 0, 0, 31.0031, 29.5798, 137.483)
    14 (0, 0)
 Node 1: XIXHYA+LinotypeFeltpen-Medium-OV-IFXHYA (31.0031, 0, 0, 31.0031, 36.3075, 137.483)
    25 (0, 0)
 Node 2: XIXHYA+LinotypeFeltpen-Medium-OV-IFXHYA (31.0031, 0, 0, 31.0031, 49.7628, 137.483)
    12 (0, 0)
...

What does it mean?

Is it also possible, that there is an interconnection between memory leaks, because it occurs, that when the pages are displayed, it sometimes prints a memory warning. For a better understanding, I use Instruments on th开发者_JAVA技巧e Simulator to detect leaks, but it couldn't find anything. Only when I test the Application on an iPad, it prints this memory leak warnings.

I didn't figure out, what the messages are meaning. I know, they occure, when a CALayer is drawing something, but anyhow it doesn't have to do something with CoreGraphics pdf leaking.

The leaks occure by my own.