Your readings indicate that the makers wiring is correct. I don’t know if your wiring is correct.
Are you sure that position 0 is 0 for input to output? You reported it as 99.6 kohms in an earlier post. A 0 value would indicate no attenuation and you should have been blasted with sound in both channels. Recheck position 17 as you have two different values for output to ground; they should be the same – ca. 14 kohms.
Keep in mind that there are only two resistors per channel in circuit at a given time. The exception would be the first and last positions which will only have one resistor and a wire and their positions should be reversed. So, all other positions should work fine. If you have some cheap headphones, you could skip the bad position and start with the next. This would at least show that your wiring is correct.
If you can contact just the top lead of the top resistor – closest to the pcb board, you may be able to determine if the resistor is bad by measuring resistance between it and the joint between the two resistors. Of course, if that solder joint is bad, you will still see infinity. Check the resistor closest to the bottom pcb as well to make sure you have the correct resistor. If both are fine – i.e. ~99 ohms not kohms, then it is a bad solder joint.
The faulty position isn’t one you are likely to use, so I wouldn’t pitch the attenuator if the seller won’t replace it. Once I knew the seller won’t replace the unit, I would try reflowing the solder at the top pcb, then, if that didn’t fix the reading, reflow solder between the two resistors. If you don’t want to replace the bad resistor, you could remove it and replace it with a wire. The sound wouldn’t be balanced at that position, but you shouldn’t get blasted in the right channel, it would be the same as the previous position for that channel. The attenuation of the left channel at the bad position is -60dB and not likely to be of any practical use.
