This one of the causes for the key stuck in ignition issue for a Pontiac G8 after you have ruled out all electrical issues such as the R8 relay. If your mirrors and sunroof are working then it is not the relay. You will notice this problem if your car is in park, your foot on the break, but the ignition switch will still not turn all the way off. This was a slow failure for me because sometimes the pin would catch the lever but it became worse and worse where the lever was always below the pin and the key was stuck with my car still "on" which will drain the battery (disconnect the black battery terminal in the trunk if that happens). You have to disassemble the center console and shifter knob to get to this. Note that the little white plastic hook is controlled by the foot brake.
In this video you can see that the pin does not always catch the lever. The flat lever has to be ABOVE the little round metal pin or it will not engage the solenoid and allow you to release the key. To fix this you have to push the pin over so it engages the lever better, and you can try to add some glue to make sure the lever does not move again for a long time (but do this with a syringe to avoid a mess). I used super glue because it's easier to work with, but you might have a better adhesive such as epoxy, but keep in mind that might be tackier and thicker and harder to work with and you don't have a lot of wiggle room to apply.
The fix video can be found here: ua-cam.com/video/ftVnqIKaRxg/v-deo.html