From that link, the one with Everlast guy in it, it says the Trafimet S series are blowback style so that is what I have.
As I said I tried different pressures, here is what the manual states
b) Check air pressure is around 4.5-5 bar (65-75PSI), excessive pressure will give bad
starting, pressure can be reduced to around 4.0 bar if necessary
I also used the flow meter on the torch itself and flow was more than adequate according to it so I must presume pressure likewise.
I will remove the extension and connect it to the central adapter and see if it works, if it does then it seems there may be a limit to the length of lead, if it doesn't then it could be an issue with the blowback parts in the torch itself.
When I asked for a 10m torch I was told they only have them in 6M but they could supply a joining box to extend, what this consisted of I am not sure but would think it just a pipe connection (double male) and 3 terminals to connect the safety wires and pilot arc wire but maybe not?