I've had breadboards like his react to air flow. Those cheap ones especially have such horrible connections that the slightest motion of flimsy part like a resi

I've had breadboards like his react to air flow. Those cheap ones especially have such horrible connections that the slightest motion of flimsy part like a resistor or LED wagging in the breeze will cause a significant change in impedance where the leads meet the contacts. Since this signal is dependent upon the series resistance, the output could vary as a result.