Why does XE7 rebuild my project when I use F5, when no files have been modified since last build?

I'm currently using XE7, and I have a project group with about a dozen VCL projects in it, some of them rather large.
When I have one of my projects selected as the active project and I click F5 to debug the application after I build the application, the IDE tries to rebuild all of the projects in the group, when it shouldn't be buildingany, since (1) nothing has been modified, and (2) I just built the project I want to debug.
This is causing me to lose quite a bit of time in my code / debug cycle. It is especially troublesome because my applications use compiler variables for conditional compilation and some units have to be rebuilt for specific projects. When the IDE tries to rebuild a project I don't have selected, it fails because a particular unit was not rebuilt. This happens despite the fact I have no inter-project dependencies defined.
I have recently discovered that if I hit F5 within 0.5 seconds after building my project, it runs without further rebuilds. If I wait any longer than that, it tries to rebuild the entire group, errors out because of the conditional compilation issue described above, and I have to start over.
Is this a known issue in XE7? Is it fixed in any later version? Is there anything I can do to fix it in XE7?