issue with loop after invoking void function arduino - arduino

Question

i've made simple program that is ligtning the RGB diod, and receiving info via i2c from keypad.
i have weird issue where i2c is not working right after invoking void function. when i switch functions with regular loop then same situation happens.
first i thought that it was connected with analog4 and analog5 port, but after changing functions it became obvious that this is not related.
after commenting Potentiometer(i) in loop method keypad is working as a charm
beneath i'm putting code
#include <Wire.h>
#include "Adafruit_MPR121.h"
Adafruit_MPR121 cap = Adafruit_MPR121();
uint16_t lasttouched = 0;
uint16_t currtouched = 0;
int RGB1[] = { 22, 23, 24 };
int RGB2[] = { 25, 26, 27 };
int RGB3[] = { 28, 29, 30 };
int RGB4[] = { 31, 32, 33 };
void setup()
{
for (int i = 0; i < 3; i++){
pinMode(RGB1[i], OUTPUT);
digitalWrite(RGB1[i], HIGH);
pinMode(RGB2[i], OUTPUT);
digitalWrite(RGB2[i], HIGH);
pinMode(RGB3[i], OUTPUT);
digitalWrite(RGB3[i], HIGH);
pinMode(RGB4[i], OUTPUT);
digitalWrite(RGB4[i], HIGH);
}
Serial.begin(9600);
Serial.println("Adafruit MPR121 Capacitive Touch sensor test");
if (!cap.begin(0x5A)) {
Serial.println("MPR121 not found, check wiring?");
while (1);
}
Serial.println("MPR121 found!");
}
void loop()
{
currtouched = cap.touched();
for (uint8_t i=0; i<12; i++) {
// it if *is* touched and *wasnt* touched before, alert!
if ((currtouched & _BV(i)) && !(lasttouched & _BV(i)) ) {
Serial.print(i); Serial.println(" touched");
}
// if it *was* touched and now *isnt*, alert!
if (!(currtouched & _BV(i)) && (lasttouched & _BV(i)) ) {
Serial.print(i); Serial.println(" released");
}
}
// reset our state
lasttouched = currtouched;
Potentiometer(0);
Potentiometer(1);
Potentiometer(2);
Potentiometer(3);
// comment out this line for detailed data from the sensor!
return;
// debugging info, what
Serial.print("\t\t\t\t\t\t\t\t\t\t\t\t\t 0x"); Serial.println(cap.touched(), HEX);
Serial.print("Filt: ");
for (uint8_t i=0; i<12; i++) {
Serial.print(cap.filteredData(i)); Serial.print("\t");
}
Serial.println();
Serial.print("Base: ");
for (uint8_t i=0; i<12; i++) {
Serial.print(cap.baselineData(i)); Serial.print("\t");
}
Serial.println();
delay(100);
}
void Potentiometer(int i){
int j = analogRead(i);
switch (i+1){
case 1:
detectColor(RGB1, j);
break;
case 2:
detectColor(RGB2, j);
break;
case 3:
detectColor(RGB3, j);
break;
case 4:
detectColor(RGB4, j);
break;
}
}
void detectColor(int i[], int j){
if (j < 25)
RGB_color(i, 0);
if (j > 25 && j < 195)
RGB_color(i, 1);
if (j > 195 && j < 365)
RGB_color(i, 2);
if (j > 365 && j < 535)
RGB_color(i, 3);
if (j > 535 && j < 705)
RGB_color(i, 4);
if (j > 705 && j < 875)
RGB_color(i, 5);
if (j > 875 && j < 1010)
RGB_color(i, 6);
if (j > 1010)
RGB_color(i, 7);
}
void RGB_color(int dioda[], int color)
{
switch (color){
case 0:
digitalWrite(dioda[0], HIGH);
digitalWrite(dioda[1], HIGH);
digitalWrite(dioda[2], HIGH);
break;
case 1:
digitalWrite(dioda[0], LOW);
digitalWrite(dioda[1], HIGH);
digitalWrite(dioda[2], HIGH);
break;
case 2:
digitalWrite(dioda[0], HIGH);
digitalWrite(dioda[1], LOW);
digitalWrite(dioda[2], HIGH);
break;
case 3:
digitalWrite(dioda[0], HIGH);
digitalWrite(dioda[1], HIGH);
digitalWrite(dioda[2], LOW);
break;
case 4:
digitalWrite(dioda[0], LOW);
digitalWrite(dioda[1], LOW);
digitalWrite(dioda[2], HIGH);
break;
case 5:
digitalWrite(dioda[0], LOW);
digitalWrite(dioda[1], HIGH);
digitalWrite(dioda[2], LOW);
break;
case 6:
digitalWrite(dioda[0], HIGH);
digitalWrite(dioda[1], LOW);
digitalWrite(dioda[2], LOW);
break;
case 7:
digitalWrite(dioda[0], LOW);
digitalWrite(dioda[1], LOW);
digitalWrite(dioda[2], LOW);
break;
}
}