Yes there are some mistakes in the team which should be resolved if they want to stand at prominent level in World Cup. But they are doing well.
Like we can take an example from the yesterday match. USA team is not a big team like others. But Pakistan was not able to defeat them. They made only 159 runs against them and USA tied the match and win the match in super over. You may see the performance of Muhammad Amir in Super over he bowled three wides and gave 18 runs in an over. Conclusion is that they have some mistakes which they should resolve and they don't decide to play with small teams only ICC decide about that.
And you shared some thoughts about the yesterday T20I World Cup match. I think they lost the match due Amir. He didn't bowl well the super over. He gave many extra runs to the USA team. And USA team took advantage of this mistake and won the match in super over. And I think the last over should be given to Naseem Shah I believe that he could bowl well but he gave over to Haris Rauf. I hope Pakistan will not make these mistakes in future. And will play well.