Following in the tracks of hanging bug

I've downloaded source, compiled it in VS2005 for PPC2003. Than modified sample TestApplication to show number of frames passed.
Unfortunately, on both tested devices this bug appears ( I hoped that may be it vanished ) After about 32000 frames on one device and 43000 on another.
Do you tried to catch this bug?
Now with the source code I could make some deeper debug and can explain what happens when game in thats hanging state. The game doesn't fully hangs, indeed it doesn't hangs at all. But picture on the screen remains the same despite the fact that onNextFrame() is called, it changed backbuffer, GXBeginDraw() called, backbuffer coppied by memcpy, GXEndDraw(), all called and returned S_OK, but picture on the screen doesn't want to update, I don't know realy what to do and to think in this situation.
Unfortunately, on both tested devices this bug appears ( I hoped that may be it vanished ) After about 32000 frames on one device and 43000 on another.
Do you tried to catch this bug?
Now with the source code I could make some deeper debug and can explain what happens when game in thats hanging state. The game doesn't fully hangs, indeed it doesn't hangs at all. But picture on the screen remains the same despite the fact that onNextFrame() is called, it changed backbuffer, GXBeginDraw() called, backbuffer coppied by memcpy, GXEndDraw(), all called and returned S_OK, but picture on the screen doesn't want to update, I don't know realy what to do and to think in this situation.