Any progress with this? Have you confronted more games with this issue? Sometimes with Lyra (using PC keyboard) I can reboot my miggy with just CTRL-Amiga (two-finger-salute) or just CTRL or Amiga reboots the computer. This has happened a couple of times. I was just editing some text with a text-editor and wanted to get '#' from the keyboard - instead I got a reset.
Entering conf mode (SHIFT-PAUSE) I can make the KB act normally again, until it goes nuts in a random-timeframe.