Build trigger inheritance in sub project?

Hi,

We have the following setup in a Teamcity version 2017.1-instance:

• Project A which builds when changes is detected in Github repository A.
• Project B with is a sub project of project A, which builds when changes are detected in Github repository B.
• They have separate VCS-roots and VCS triggers defined.
• Repository A is a total clone of repository B.  

The problem is that Project B triggers builds when a change has been done to repository A, so I wonder if the VCS trigger of project B somehow listens to changes in VCS roots of the parent project A aswell? 

Brgds

Jonas