I've got a hierarchy of this type: sites (polys) -> features (points) -> hazards (tabular) -> actions (tabular). I can drill all the way down to actions and if there are any, I can edit and submit the changes successfully. However, I can't add a new action to an existing hazard (there is no add button). An article from 2015 (below) says that Collector only supports relationships 3 levels deep and I'm wondering if this is still the case (and hence is preventing the add button form being displayed for actions). Related Tables – Exploring New Ways to use Collector for ArcGIS