diff --git a/src/workflow/event.rs b/src/workflow/event.rs
index 3e40e47..faf36f3 100644
--- a/src/workflow/event.rs
+++ b/src/workflow/event.rs
@@ -198,7 +198,7 @@ pub struct GenericEvent {
 #[derive(Deserialize, Serialize, Debug)]
 #[serde(rename_all = "kebab-case")]
 pub struct PullRequest {
-    #[serde(default)]
+    #[serde(default, deserialize_with = "crate::common::scalar_or_vector")]
     pub types: Vec<String>,
 
     #[serde(flatten)]
diff --git a/tests/sample-workflows/zizmor-issue-650.yml b/tests/sample-workflows/zizmor-issue-650.yml
new file mode 100644
index 0000000..14a28ee
--- /dev/null
+++ b/tests/sample-workflows/zizmor-issue-650.yml
@@ -0,0 +1,31 @@
+# See https://github.com/woodruffw/zizmor/issues/650
+
+# Copyright © Michal Čihař <michal@weblate.org>
+#
+# SPDX-License-Identifier: CC0-1.0
+
+# This file is maintained in https://github.com/WeblateOrg/meta/
+
+name: Pull request automation
+
+on:
+  pull_request_target:
+    types: opened
+
+permissions:
+  contents: read
+
+jobs:
+  weblate_automerge:
+    permissions:
+      pull-requests: write
+      contents: write
+    runs-on: ubuntu-24.04
+    name: Weblate automerge
+    if: github.actor == 'weblate'
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - name: Enable Pull Request Automerge
+        run: gh pr merge --rebase --auto "${{ github.event.pull_request.number }}"
+        env:
+          GH_TOKEN: ${{ secrets.WEBLATE_CI_TOKEN }}