Tokens in "contextual filters" do not work

Parent view lists "folder" nodes, child view lists "files". Both files and folders use Node Hierarchy module to maintain parent-child relationships.
Parent view has 3 regular fileds: nid, parent nid (via relationship), title and views-field that uses [!nid_1] (current nid) as contextual filter for the child view.

Child view expects a parent_id and shows child files (if any) or nothing (hidden) if argument is not there. Live preview with correct argument shows what I want. Parent view with static "contextual filter" value (say, "8") works too — I get nice tree view of folders with the same list of node 8 child files.

1. If I set contextual filters to [!nid_1] (it's current row nid) I get "Recursion, stop!" if "Aggregate queries" is not enabled.
2. If I turn on "aggregate" I get "Warning: Invalid argument supplied for foreach() in views_plugin_query_default->compile_fields()",.
3. "Aggregate is On, child view set to "Display all results for the specified field" — see 1, recursion stop!
4. Even if I use Global-Custom text filed with value 8 and its token [!nothing] as a contextual filter I still get 'recursion stop".
5. Same result if I leave the filter blank.

Looks like nothing is passed to the child view.