There are two variants of using nested fields in Foreman, if we use add_child_link helper and the subform contains select, the select2 does not work correctly in added subform. The issue is that select2 was initialized for the template form and copying does not consider links (not sure if it's even possible). To fix this we should destroy select2 in template and reinitialize upon adding the copy of it. I think this could fix smart variable issue Shlomi has mentioned (https://github.com/theforeman/foreman/pull/2415#issuecomment-109982033) but I'm unable to verify because of #10878