Just to clarify, the mission activity you are missing is for "Posted a Reply to a Question," since your replies were not marked as "Answered." The daily limit for the mission, "Posted a Reply to a Question" is set at 20.
From your Activity page, I count that you have been awarded this mission 20 times in the past 10 hours. So, yes, you have hit the point limit for that mission today. However, if any of your posts are Liked or Marked as Helpful or Marked as Correct, you will receive points for those missions until the daily max is reached for them.
Qlik Community Team