Uh not to sound like a ton of bricks, but what is a "pullup capacitor"? You mean the connection to the chip's Vcc was a capacitor (effectively blocking any DC current, and not powering the chip), instead of just a trace?
Yes, clearly someone had meant to put a resistor there but instead spec'd a cap, making an open circuit instead. Shorting out the cap solved the problem.
Since they'd shipped these boards for a while it was pretty likely nobody was using them. Since nobody wants to design around a part likely to be cancelled due to poor performance in the market...we figured nobody would be relying on this part.
I called it a "pullup capacitor" because it was where you'd expect to see a pullup resistor and thus the name is funny.
