diff --git a/pagure/internal/__init__.py b/pagure/internal/__init__.py
index ed939e6..b07e6c0 100644
--- a/pagure/internal/__init__.py
+++ b/pagure/internal/__init__.py
@@ -316,6 +316,14 @@ def get_pull_request_ready_branch():
                     break
                 branch_commits.append(branch_commit.hex)
 
+            # If master is ahead of branch, we need to remove the commits
+            # that are already in master
+            branch_commits = [
+                com
+                for com in branch_commits
+                if com.oid.hex not in main_commits
+            ]
+
             if branch_commits:
                 branches[branchname] = branch_commits
 
diff --git a/pagure/lib/git.py b/pagure/lib/git.py
index bcc17cf..702119a 100644
--- a/pagure/lib/git.py
+++ b/pagure/lib/git.py
@@ -1397,6 +1397,14 @@ def diff_pull_request(
 
             diff_commits.append(branch_commit)
 
+        # If master is ahead of branch, we need to remove the commits
+        # that are already in master
+        diff_commits = [
+            com
+            for com in diff_commits
+            if com.oid.hex not in main_commits
+        ]
+
         if request.status and diff_commits:
             first_commit = repo_obj[diff_commits[-1].oid.hex]
             # Check if we can still rely on the merge_status
diff --git a/pagure/ui/fork.py b/pagure/ui/fork.py
index 1e8d0ce..e8923fc 100644
--- a/pagure/ui/fork.py
+++ b/pagure/ui/fork.py
@@ -116,6 +116,14 @@ def _get_pr_info(repo_obj, orig_repo, branch_from, branch_to):
 
             diff_commits.append(branch_commit)
 
+        # If master is ahead of branch, we need to remove the commits
+        # that are already in master
+        diff_commits = [
+            com
+            for com in diff_commits
+            if com.oid.hex not in main_commits
+        ]
+
         if diff_commits:
             first_commit = repo_obj[diff_commits[-1].oid.hex]
             if len(first_commit.parents) > 0: