Incorrect total count of github check runs


I am about to add Github check badges for my repo, just like this:

When I check the results of my repo thru the api only to find that there is no check runs at all:

  "total_count": 0,
  "check_runs": [


However, there are some checks in the latest pull request (link), why is the total count still 0? Am I missing something important? Thanks in advance!