It seems like $template can also be of type array and null; however, parameter $site of Aimeos\Bootstrap::getSetupPaths() does only seem to accept string, maybe add an additional type check?
Ignorable by Annotation
If this is a false-positive, you can also ignore this issue in your code via the ignore-type annotation
The type Aimeos\Shop\Command\Associative was not found. Maybe you did not declare it correctly or list all dependencies?
The issue could also be caused by a filter entry in the build configuration.
If the path has been excluded in your configuration, e.g. excluded_paths:["lib/*"],
you can move it to the dependency path list as follows: