Templates are not scanned for dependent projects of active project in solution.

[malylemire1]

Active project in solution dependencies should be scanned for templates.

[bennor]

Can you elaborate a bit?

[malylemire1]

If you build a project and you have a reference to a dll that is produced by another loaded project in the solution, the referenced project is built. Currently, if that referenced project contains a template with AutoT4 settings to BeforeBuild or AfterBuild, it is not executed.