Why does GitHub show double the number of commits?

Question

GitHub

There are 15 commits

in the project Published the project on GitHub. The project itself also has 15 commits.

But for some reason, in activity and in the graph, it shows a total of 30 commits

. Profile (if you need to look): https://github.com/OttoAndrey
The project itself: https://github.com/OttoAndrey/human_match

UPD :
Wrote to GitHub support. They don’t know why this happens, but they rebuilt the stat by commits and now everything is ok with me.

UPD2:
Crutch solution: you can go to your account settings and add one more mail, in addition to the main one, github will start recalculating statistics and start displaying the correct number of commits.