08 Individual relay drive by (TPIC6B595)

Projects Programming
7

That is strange. I can't see a reason why it would do that. Try this change:

void updateShiftRegister()
{
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, MSBFIRST, leds);
  digitalWrite(latchPin, HIGH);
  Serial.print("leds=");
  Serial.println(leds, BIN);
}

What do you see on serial monitor?