Even although there are two outputs which are connected somewhere in the circuit there could be a bad connection or high resistance between the interconnected points and the cyl 3 output.
My advice to people is always use original quality plugs, leads and coils as anything less is usually at least, not as good, and at worst pure garbage that leads you round in circles doing diagnostics.
I honestly went around in circles for about a month many years back chasing intermittent misfires with my petrol landy, I was using all brand new parts but aftermarket ones and kept having issues. I eventually grew suspicious and got original coils, leads and plugs from a scrap yard car and it ran perfect with them fitted. I left the scrappy parts in there and binned all the shiny new stuff which was 2 new coils, 2 pairs of leads and a set of eBay ngk plugs which turned out to be fake lol , all shiny new and none of it worked properly. Nowadays I even put top brand stuff in the old “beaters with heaters” that I drive.
My advice to people is always use original quality plugs, leads and coils as anything less is usually at least, not as good, and at worst pure garbage that leads you round in circles doing diagnostics.
I honestly went around in circles for about a month many years back chasing intermittent misfires with my petrol landy, I was using all brand new parts but aftermarket ones and kept having issues. I eventually grew suspicious and got original coils, leads and plugs from a scrap yard car and it ran perfect with them fitted. I left the scrappy parts in there and binned all the shiny new stuff which was 2 new coils, 2 pairs of leads and a set of eBay ngk plugs which turned out to be fake lol , all shiny new and none of it worked properly. Nowadays I even put top brand stuff in the old “beaters with heaters” that I drive.