Data processing (yes, there's an error), it means the G6 is writing the save from the last game you played to the file .0
It always did that, but there weren't any message.
The Firmware 4.2a is buggy, games are crashing.
just downgrade to 4.2 or wait a new version.
The games are sorting with the FAT order, and depends on the size of the files deleted/added. (you delete the 1st game added on the card, the next game you'll add will be on the 1st line)
My G6 not lite is working like this, I dont know about G6L.