pontoni masher mastery bugged
What I did was park an L80 there and started up the toon every time I was swapping characters. (Well, if no one was waiting for me.) Even without watching the event timers, eventually he’s available. At that point, I called out in /map, waited for anyone who said they were on the way, and voila.
I also had tried it your way, waiting for the event chain to be up, guiding him to his spot, and… well, I got bored of waiting before he was ready (there seems to be some sort of cooldown between the last event in the chain and he’s being willing to fight).
Since the map resets itself frequently (due to the TD meta), it’s unlikely that Potoni is permanently bugged. (Although if it happens to you again, use the in-game /bug reporting tool, to give the ANet tech team additional data to help them troubleshoot.)
tl;dr park a toon there; keep showing up until you get lucky on the time. It’s not ideal, but it worked well for my level of impatience.
John Smith: “you should kill monsters, because killing monsters is awesome.”