Sounds like you have a short on your board. With a 10k pullup and the pin set to input you should have 5V. Can you remove the chip and measure the voltage to see if it is a short?
All peripherals except Power PWM control are disabled so I do not know what else to do. Wherever that pin is alluded to in the datasheet, it is shown involved with the EUSART only.
It was not a short but an open circuit!. The pin was floating, not seeing the 5V. I started to suspect that when found that for the first two seconds it was reading a 1 and then a 0.
Measured the voltage directly on the pin, with the micro in RESET and found that.
I just regret the so many hours checking software.