So was the guy your boss or not? What kind of organization lets someone promote themselves to project manager or the boss of other engineers?
People just sort of assumed that he had been appointed project manager after that.
This kind of behavior, to me, speaks to me of dysfunctional management and I think it's probably good in the long term to get out of that kind of situation.
Lesson to be learned: You can't ignore others on the team. You can't have clear separation of duties without strong management or a good working trust relationship. Both of these are weakened if you're remote most or all of the time and the culture doesn't reward/support remote workers.