Is it a problem that can be fixed? We saw the same thing under Sarri. Start off brilliantly but collapse after the slightest amount of pressure.
Also, you bring up creating chances, yet the only real chances we create is from the result of forcing the opposition to make a mistake when we press them. Other than that, there is no creativity in this team. When our attackers and midfield tire, the chances dry up and the other team takes control. We saw it against United, Liverpool, and now today. I think it's wishful thinking to expect we will create chances out of nothing. There's a reason we saw little to no comebacks last season.
This is where I though bringing off Mount for Barkley would've paid off, as Barkley would've looked to create something. I'll give Tammy a few more games before we can safely say waiting for him to break his duck will hinder us even more.