sometimes having two tests apearing in github instead of one

So all my teamcity builds are connected to my git repositories, and when im creating a pull request, i get a "TeamCity build started" message at the bottom, which is good.

My problem is, that sometimes, lets say my build configuration name is X, then i get two messages:

1: X ("my project name") TeamCity build started 

2: X ("my project name") -merge TeamCity build started 

I don't understand why i get two, and where is this "merge" message comes from (its before i merged the pull request)

Any idea?

thanks!