Node with id xxx has undefined data!

The bug appears again when opening a workflow without nodes while a workflow with nodes is depicted on canvas.

{
  "graph": {
    "id": "Emtpy",
    "label": "Emtpy",
    "category": "11"
  },
  "links": [],
  "nodes": []
}

Also if nodes contain an empty object only the bug will not appear but the workflow on canvas wont change at all!

{
  "graph": {
    "id": "Emtpy",
    "label": "Emtpy",
    "category": "11"
  },
  "links": [{}],
  "nodes": [{}]
}