I just made this yeast starter and it looked normal until I pitched the yeast. Now it's almost a greenish/brown color? The yeast was WL001 and was purchased from my local homebrew shop and had an expiry date in December?
Doesn't look abnormal to me, I wouldn't worry about it... Why such a small stater tear in that 2L flask? I usually run 1600-1800 mL in that thing for a couple days and get a nice thick yeast cake!