Since rev. https://github.com/odoo/odoo/commit/ebd17217c4e7e9ff06d97028de64fb2fc44d6266 the attribute `_editionViewType` has been introduced to use the modifiers from the correct one2many view type. This attribute wasn't correctly populated if multiple one2manys were imbricated. The first view type (form in the test case) was set for the second one2many even though the view type was list. This was due to the `visitChildren` function use that browses through all levels (and not only the first one). To reproduce the bug before this rev. you could try to create a new survey, add a question (one2many) then select multiple choice and add an answer (one2many editable).