Battlefield 5 reward

Product: Battlefield V
Platform:Sony Playstation 4
Please specify your platform model. Sony PlayStation 4 Pro
Which part of the game is the issue happening in? Single Player War Story
Which part of the mode? Nordlys
Please select your region Europe
On which server did this happen? Single Player
When did this happen? (dd.mm.yy hh:mm) 01.DEC.2018 11:00
Summarize your bug Hey guys, could you help me please? In the act ”ALL IS ASH” I have a visual bug, it says that I have completed all the tasks, but in menu it shows to me that I have to complete 2 challenges more, ”warm up at all the camp fires” and ”stay undetected in the storm”. I cannot get the achievement because of this bug, please reply, thanks. At the end of the act it still shows me that I have all the challenges complete and the letters, but when I go back to main menu it shows that I have to complete the other two challenges.
How often does the bug occur? Every time (100%)
Steps: How can we find the bug ourselves? You can find it by playing the act ”ALL IS ASH” and trying to complete all the tasks.
What happens when the bug occurs? Actually, nothing, but I cannot get that skin knife.
What should be happening instead? It should give me the reward: a melee weapon.

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I do not understand, if I try to restart the mission, the act ”ALL IS ASH”, it shows me the same thing that I completed everything in this act and in all the other acts, but at the end of ”NORDLYS” it appears that I have finished NORDLYS, I have all the 14 letters and I have 8/10 challenges. I really want to complete these tasks, please help me. Thanks you!