Inconsistency/Differenct Voltage Each Output Op Amp LM324
The op-amps on an LM324 chip are essentially identical to each other (differences would be in mV) and you've swapped the chip so your circuit implementation must be faulty. So maybe you have a wrong or defective resistor or some conductive stuff on the PCB or you have a capacitor on the output that you think doesn't matter - whatever it is is something you have done.