The SNES problem units were the earlier, heavier type. By around 1994, the newer, lighter models have from what I've seen, failed to yellow. The cause I believe was the amount or type of flame retardant chemical used, and obviously also due to the lighter color of the console.
I am extremely surprised this would also be happening to a Gamecube, because I would have assumed Nintendo would have learned their lesson by then. Very dumb.