diff --git a/contrib/buildbot/phabricator_wrapper.py b/contrib/buildbot/phabricator_wrapper.py
--- a/contrib/buildbot/phabricator_wrapper.py
+++ b/contrib/buildbot/phabricator_wrapper.py
@@ -474,7 +474,8 @@
                 )
             )
 
-    def update_build_target_status(self, build_target, build_id, status):
+    def update_build_target_status(
+            self, build_target, build_id=None, status=None):
         harbormaster_build_status_mapping = {
             BuildStatus.Queued: "work",
             BuildStatus.Running: "work",
@@ -482,7 +483,8 @@
             BuildStatus.Failure: "fail",
         }
 
-        build_target.update_build_status(build_id, status)
+        if build_id and status:
+            build_target.update_build_status(build_id, status)
 
         self.harbormaster.sendmessage(
             buildTargetPHID=build_target.phid,
diff --git a/contrib/buildbot/server.py b/contrib/buildbot/server.py
--- a/contrib/buildbot/server.py
+++ b/contrib/buildbot/server.py
@@ -305,7 +305,11 @@
                 properties)['id']
             build_target.queue_build(build_id, build_name)
 
-        create_server.db['diff_targets'][target_phid] = build_target
+        if len(build_target.builds) > 0:
+            create_server.db['diff_targets'][target_phid] = build_target
+        else:
+            phab.update_build_target_status(build_target)
+
         return SUCCESS, 200
 
     @app.route("/land", methods=['POST'])
diff --git a/contrib/buildbot/test/test_endpoint_buildDiff.py b/contrib/buildbot/test/test_endpoint_buildDiff.py
--- a/contrib/buildbot/test/test_endpoint_buildDiff.py
+++ b/contrib/buildbot/test/test_endpoint_buildDiff.py
@@ -70,6 +70,10 @@
             self.phab.differential.getcommitpaths.assert_called()
             self.phab.get_file_content_from_master.assert_called()
 
+            if len(expectedBuilds) == 0:
+                self.phab.harbormaster.sendmessage.assert_called_with(
+                    buildTargetPHID=data.targetPHID, type="pass")
+
             expected_calls = [
                 call(AnyWith(requests.PreparedRequest, {
                     "url": "https://teamcity.test/app/rest/buildQueue",
diff --git a/contrib/buildbot/test/test_phabricator.py b/contrib/buildbot/test/test_phabricator.py
--- a/contrib/buildbot/test/test_phabricator.py
+++ b/contrib/buildbot/test/test_phabricator.py
@@ -9,6 +9,7 @@
 import os
 import unittest
 
+from build import BuildStatus, BuildTarget
 from phabricator_wrapper import BITCOIN_ABC_PROJECT_PHID, BITCOIN_ABC_REPO
 import test.mocks.phabricator
 
@@ -441,6 +442,41 @@
         with self.assertRaisesRegex(AssertionError, "Failed to edit panel"):
             call_set_text_panel_content()
 
+    def test_update_build_target_status(self):
+        build_target = BuildTarget("PHID-HMBT-1234")
+
+        # With no builds queued, default to pass
+        self.phab.update_build_target_status(build_target)
+        self.phab.harbormaster.sendmessage.assert_called_with(
+            buildTargetPHID=build_target.phid, type="pass")
+
+        # Queue a build
+        build_target.queue_build("build-1", "build-name")
+        self.phab.update_build_target_status(build_target)
+        self.phab.harbormaster.sendmessage.assert_called_with(
+            buildTargetPHID=build_target.phid, type="work")
+
+        # Test various statuses
+        self.phab.update_build_target_status(
+            build_target, "build-1", BuildStatus.Queued)
+        self.phab.harbormaster.sendmessage.assert_called_with(
+            buildTargetPHID=build_target.phid, type="work")
+
+        self.phab.update_build_target_status(
+            build_target, "build-1", BuildStatus.Running)
+        self.phab.harbormaster.sendmessage.assert_called_with(
+            buildTargetPHID=build_target.phid, type="work")
+
+        self.phab.update_build_target_status(
+            build_target, "build-1", BuildStatus.Failure)
+        self.phab.harbormaster.sendmessage.assert_called_with(
+            buildTargetPHID=build_target.phid, type="fail")
+
+        self.phab.update_build_target_status(
+            build_target, "build-1", BuildStatus.Success)
+        self.phab.harbormaster.sendmessage.assert_called_with(
+            buildTargetPHID=build_target.phid, type="pass")
+
     def test_get_object_token(self):
         user_PHID = "PHID-USER-foobarbaz"
         self.phab.user.whoami.return_value = {