diff --git a/tests/base.py b/tests/base.py
index 8cbe7a6c6c..7c063e68c8 100644
--- a/tests/base.py
+++ b/tests/base.py
@@ -1909,7 +1909,8 @@ class FakeGithubPullRequest(object):
 
     def __init__(self, github, number, project, branch,
                  subject, upstream_root, files=[], number_of_commits=1,
-                 writers=[], body=None, body_text=None, draft=False):
+                 writers=[], body=None, body_text=None, draft=False,
+                 base_sha=None):
         """Creates a new PR with several commits.
         Sends an event about opened PR."""
         self.github = github
@@ -1936,7 +1937,7 @@ class FakeGithubPullRequest(object):
         self.merge_message = None
         self.state = 'open'
         self.url = 'https://%s/%s/pull/%s' % (github.server, project, number)
-        self._createPRRef()
+        self._createPRRef(base_sha=base_sha)
         self._addCommitToRepo(files=files)
         self._updateTimeStamp()
 
@@ -2103,10 +2104,11 @@ class FakeGithubPullRequest(object):
         repo_path = os.path.join(self.upstream_root, self.project)
         return git.Repo(repo_path)
 
-    def _createPRRef(self):
+    def _createPRRef(self, base_sha=None):
+        base_sha = base_sha or 'refs/tags/init'
         repo = self._getRepo()
         GithubChangeReference.create(
-            repo, self.getPRReference(), 'refs/tags/init')
+            repo, self.getPRReference(), base_sha)
 
     def _addCommitToRepo(self, files=[], reset=False):
         repo = self._getRepo()
@@ -2354,11 +2356,13 @@ class FakeGithubConnection(githubconnection.GithubConnection):
         self.zuul_web_port = port
 
     def openFakePullRequest(self, project, branch, subject, files=[],
-                            body=None, body_text=None, draft=False):
+                            body=None, body_text=None, draft=False,
+                            base_sha=None):
         self.pr_number += 1
         pull_request = FakeGithubPullRequest(
             self, self.pr_number, project, branch, subject, self.upstream_root,
-            files=files, body=body, body_text=body_text, draft=draft)
+            files=files, body=body, body_text=body_text, draft=draft,
+            base_sha=base_sha)
         self.pull_requests[self.pr_number] = pull_request
         return pull_request
 
diff --git a/tests/fakegithub.py b/tests/fakegithub.py
index 28f0203eaa..ec99832e48 100644
--- a/tests/fakegithub.py
+++ b/tests/fakegithub.py
@@ -687,9 +687,24 @@ class FakeGithubClient(object):
             return re.match(r'[a-z0-9]{40}', s)
 
         if query_is_sha(query):
-            return (FakeIssueSearchResult(FakeIssue(pr))
-                    for pr in self._data.pull_requests.values()
-                    if pr.head_sha == query)
+            # Github returns all PR's that contain the sha in their history
+            result = []
+            for pr in self._data.pull_requests.values():
+                # Quick check if head sha matches
+                if pr.head_sha == query:
+                    result.append(FakeIssueSearchResult(FakeIssue(pr)))
+                    continue
+
+                # If head sha doesn't match it still could be in the pr history
+                repo = pr._getRepo()
+                commits = repo.iter_commits(
+                    '%s...%s' % (pr.branch, pr.head_sha))
+                for commit in commits:
+                    if commit.hexsha == query:
+                        result.append(FakeIssueSearchResult(FakeIssue(pr)))
+                        continue
+
+            return result
 
         # Non-SHA queries are of the form:
         #
diff --git a/tests/unit/test_github_requirements.py b/tests/unit/test_github_requirements.py
index e542f80f96..bde2c5ca8d 100644
--- a/tests/unit/test_github_requirements.py
+++ b/tests/unit/test_github_requirements.py
@@ -92,6 +92,11 @@ class TestGithubRequirements(ZuulTestCase):
         project = 'org/project2'
         A = self.fake_github.openFakePullRequest(project, 'master', 'A')
 
+        # Create second PR which contains the head of A in its history. Zuul
+        # should not get disturbed by the existence of this one.
+        self.fake_github.openFakePullRequest(
+            project, 'master', 'A', base_sha=A.head_sha)
+
         # An error status should not cause it to be enqueued
         self.fake_github.setCommitStatus(project, A.head_sha, 'error',
                                          context='tenant-one/check')
diff --git a/zuul/driver/github/githubconnection.py b/zuul/driver/github/githubconnection.py
index da242401ee..514e0c087d 100644
--- a/zuul/driver/github/githubconnection.py
+++ b/zuul/driver/github/githubconnection.py
@@ -1660,16 +1660,25 @@ class GithubConnection(BaseConnection):
         issues = list(github.search_issues(sha))
 
         log.debug('Got PR on project %s for sha %s', project_name, sha)
-        if len(issues) > 1:
-            raise Exception('Multiple pulls found with head sha %s' % sha)
-
         if len(issues) == 0:
             return None
 
-        pr_body = self._getChange(
-            project, issues.pop().issue.number, sha, event=event).pr
-        self._sha_pr_cache.update(project_name, pr_body)
-        return pr_body
+        # Github returns all issues that contain the sha, not only the ones
+        # with that sha as head_sha so we need to get and update all those
+        # changes and then filter for the head sha before we can error out
+        # with multiple pulls found.
+        found_pr_body = None
+        for item in issues:
+            pr_body = self._getChange(
+                project, item.issue.number, sha, event=event).pr
+            self._sha_pr_cache.update(project_name, pr_body)
+            if pr_body['head']['sha'] == sha:
+                if found_pr_body:
+                    raise Exception(
+                        'Multiple pulls found with head sha %s' % sha)
+                found_pr_body = pr_body
+
+        return found_pr_body
 
     def getPullReviews(self, pr_obj, project, number, event):
         log = get_annotated_logger(self.log, event)