Pakistan lost the match against Afghanistan. I think Pakistan lost start when Usama Mir did bowl and Rizwan dropped the catch.
In this match, we again see that Pakistan's fielding is very poor, Pakistan lost the match because of today's fielding, and we saw the same in the Australia's match, where they had a poor display of fielding.
In both matches, Pakistan's fielding is not as good as it should be. That was an important match for Pakistan to qualify in the Semi-Final and Pakistan lost it, now Pakistan has just one chance which is to win all the remaining matches and if Pakistan lost any one match of the remaining matches, then they are dependent on other teams as usual.
I don't think today we have issue with fielding because Pakistan lost match when they have target less than 300 which is surely now important for them if they want to win any game here in India with pitches mostly are not helping bowlers, and they need good target for defending and their spin bowling quality is also less the average which is another cause of defeat in this third match. Pakistan's batting still playing their cricket which was famous in 90s and giving them good results, but now it's all change which is important for the win in big event like this.
Usama Mir is not quality spinner with having no good record and other Pakistani spinners are also having not quality like Afghanistan and India which is creating problems for them in last few years with fielding is also the biggest problem, but it's never been settled which is also a fact with this team in last few years.