diff --git a/oca_port/port_addon_pr.py b/oca_port/port_addon_pr.py
index a1594de..480d354 100644
--- a/oca_port/port_addon_pr.py
+++ b/oca_port/port_addon_pr.py
@@ -816,7 +816,7 @@ def get_commits_diff(self):
                 continue
             # Get related Pull Request if any
             pr = self._get_original_pr(commit)
-            if pr:
+            if pr and pr.number != "_":  # _ stands for "Fake PR"
                 for pr_commit_sha in pr.commits:
                     try:
                         raw_commit = self.app.repo.commit(pr_commit_sha)
@@ -962,3 +962,15 @@ def _get_original_pr(self, commit: g.Commit):
             }
             self.app.cache.store_commit_pr(commit.hexsha, data)
             return g.PullRequest(**data)
+        else:
+            # Fake PR hosting orphaned commits
+            data = {
+                "number": "_",
+                "url": "",
+                "author": "",
+                "title": "",
+                "body": "",
+                "merged_at": "",
+                "commits": [],
+            }
+            self.app.cache.store_commit_pr(commit.hexsha, data)