source/blender/editors/include/ED_viewer_path.hh

@@ -70,7 +70,8 @@ enum class UpdateActiveGeometryNodesViewerResult {
 
 /**
  * Checks if the node referenced by the viewer and its entire context is still active, i.e. some
- * editor is showing it.
+ * editor is showing it. If not, the viewer path might be updated in minor ways (like changing the
+ * repeat zone iteration).
  */
 UpdateActiveGeometryNodesViewerResult update_active_geometry_nodes_viewer(const bContext &C,
                                                                           ViewerPath &viewer_path);

source/blender/editors/util/ed_viewer_path.cc

@@ -415,6 +415,7 @@ UpdateActiveGeometryNodesViewerResult update_active_geometry_nodes_viewer(const
         }
         if (!BKE_viewer_path_equal(&viewer_path, &tmp_viewer_path)) {
           std::swap(viewer_path, tmp_viewer_path);
+          /* Make sure the viewed data becomes available. */
           DEG_id_tag_update(snode.id, ID_RECALC_GEOMETRY);
           return UpdateActiveGeometryNodesViewerResult::Updated;
         }