[Bug] Notion node validator false positive: required property 'title' reported empty when set via expression (regression 2.69.2 → 2.72.0)

Summary

Since 2.72.0, workflow validation reports a false positive on the Notion node (n8n-nodes-base.notion, typeVersion: 2.2, resource: databasePage): a required title property that is set — via an n8n expression — is reported as empty.

<node>: required property 'title' cannot be empty

The same workflow validates clean on 2.69.2.

Reproduction

Validate this workflow with validate_workflow:

{
  "name": "notion-title-expression-repro",
  "nodes": [
    { "parameters": {}, "id": "00000000-1111-2222-3333-444444444444",
      "name": "Manual Trigger", "type": "n8n-nodes-base.manualTrigger",
      "position": [0, 0], "typeVersion": 1 },
    { "parameters": {
        "resource": "databasePage",
        "databaseId": { "__rl": true, "mode": "list",
          "value": "00000000-0000-0000-0000-000000000000",
          "cachedResultName": "example-db" },
        "propertiesUi": { "propertyValues": [
          { "key": "URL|url",         "urlValue":    "={{ 'https://example.com' + $json.path }}" },
          { "key": "title|title",     "title":       "={{ $json.title }}" },
          { "key": "abstract|rich_text", "textContent": "={{ $json.abstract }}" }
        ] },
        "options": {} },
      "id": "11111111-2222-3333-4444-555555555555",
      "name": "Store Page", "type": "n8n-nodes-base.notion",
      "position": [220, 0], "typeVersion": 2.2 }
  ],
  "connections": { "Manual Trigger": { "main": [[{ "node": "Store Page", "type": "main", "index": 0 }]] } }
}

Expected (and what 2.69.2 returns): valid: true, errorCount: 0. Actual (2.72.0 and later): one error, required property 'title' cannot be empty.

Which versions

An automated nightly gate validates our whole workflow set against each new image before promoting it. Verdicts for the affected workflow:

Version	Verdict
2.68.4, 2.69.0, 2.69.2	green
2.72.0, 2.73.0, 2.74.1, 2.75.1	red — this error

So the regression lands between 2.69.2 and 2.72.0 (we never tested 2.70.x/2.71.x). Nothing changed on our side: the same stored workflow flips verdict with the image alone.

What narrows it down

In the same node, two other property types also hold expressions and are not flagged — only title is:

Property	Value field	Flagged?
URL|url	urlValue	no
abstract|rich_text	textContent	no
title|title	title	yes

So this does not look like a blanket rejection of expression values, but something specific to how the required title property is read. Note that each Notion property type stores its value under a different key (urlValue, textContent, title, date…).

Minor, possibly related: the error message lower-cases the node name (store abstract notion for a node actually named Store Abstract Notion).

Impact

We hold at 2.69.2 because our promotion gate treats a new validation error as a regression, and we would rather not promote a validator that reports a healthy workflow as broken. Happy to run any patch or debug build against the same set.