The resource importer always updates every instance in the portal. This is not an issue when targeting the site template.
But when resources-importer-target-value is set to target a site, it will also perform this update in every instance.
Especially when targeting a guest site by setting
resources-importer-target-value=Guest, the guest site in every instance will be updated, which is probably not wanted behavior.
This could be fixed by being able to also specify a target portal instance in liferay-plugin-package.properties