Don't be fooled by clean looking brake fluid. BF is hydrophilic meaning it absorbs moisture over time and thus reduces braking efficiency and will eventually corrode internal brake components. I do occasional track days with my Porsche and am familiar with brake fade caused by hot or old brake fluid. It's a scary situation especially coming into turn 10 at Road Atlanta where you have to pull it down from 110 mph in time for a 90 degree turn. It is recommended to flush the system before EVERY track event, even if the juice is 2 weeks old.
I can't say that this is definately your problem, but, if your records do not show a brake system flush, I'd bet it's never been done. Even if it doesn't solve your problem, you should do it anyway. I'd be surprised if the poor brake performance is related to glaze....especially on a street car. Change out the juice and I'd bet you'll notice improvement.
Just my 2 cents.