Hello,
I have a problem !

I use 2 adc-ports AN0 and AN1
On AN0 there is an table signal 1,27V.
On AN1 there is a stable signal 2,7V.

At each port I use a resistor (22k or 10k) to protect the port and 10nF in order to filter any spikes.

I measured the signals and found out:
At port AN0 the signal has 1,27V and "in front of" the resistor 1,27V too.
But at AN1 i measure 2,8V at the port-pin and "in front of" the resistor 2,7V.
AN1 seems to have an pull-up....

what the f... ?