My SwapMagic does that too if I'm not careful - it's because I warped the modded lid slightly by mistake so it sometimes releases the eject/reset switch when I swap the discs causing the PS2 to do that Easy workaround is I make sure I hold down the top and bottom left corners of the lid when opening the cover, swapping the disc, and closing so the switch doesn't get released, and I've never had a problem since