Default.png displayed as app enters foreground

When resuming my suspended app, either by selecting it from the taskbar or from the springboard, the Default.png image is displayed instead of the applications previous state, until the app has focus.

The app is definitely suspending and resuming correctly and as soon as the transition effect has finished (either the app zooming in, or swapping) the app renders correctly from where it was suspended.

It seems that there is a problem with the snapshot mechanism that stores the last state before suspending the app.

Can anybody help me with this matter? Apple would reject my app on this reson.