Dependencies attributes resolving in a build chain

Hi All,
I have a pretty weird question, supposing to have a build chain like this:


where the dependency in blue are artifact dependency on the last succesful build  and the one in black is an artifact dependency on the same chain plus a snapshot dependency.
In this situation it may happen that bt2 and bt3 depends on different bt1 version ( I know is not exaclty the best way to manage dependencies, please don't ask me why i'm setting up this scenario :) )

How does TC resolve dep parameters in bt3,  like for instance %dep.bt1.system.build.number% in build bt3 ? Are there any resolving rules ? Is it Random based?
Empirically I found that the version from the blue side of the chain is preferred anyone knows why?


Thanks
Domenico