Sometimes it is tricky to get a good connection with the tip of the probe, so that you can get an accurate measurement. Since your measurements are inconsistent, I suggest taking each measurement more than once, until you are confident about the result. And for resistance you can switch the order of the probes too. Like measure first with the red probe on 2 and black on 3, then with black on 3 and red on 2. Make sure they agree.
Expensive probes have this difficulty too, especially if the surface you are measuring is not pristine. I just hope the measurements are accurate because it’s all we have to make the diagnosis.