GPIO_143 dropped from 1V8 to 0V12

Hello everybody,
I was recently working with GPIO_143 which is actually the PIN 8 of
the Expansion header when MUX 4 selected.
The GPIOs have normally 1.8V once set to high level. However, only the
GPIO_143 has 120mV now.
Does anyone know the reason and/or the way to have the 1.8V for high
level?
Thanks a lot,
Frederico