diff --git a/services/project-history/app/js/FlushManager.js b/services/project-history/app/js/FlushManager.js
index 526aa57876..cc14277791 100644
--- a/services/project-history/app/js/FlushManager.js
+++ b/services/project-history/app/js/FlushManager.js
@@ -28,37 +28,18 @@ export function flushIfOld(project_id, cutoffTime, callback) {
       if (err != null) {
         return callback(OError.tag(err))
       }
-      // in the normal case, the flush marker will be set with the
-      // timestamp of the oldest operation in the queue by docupdater
-      if (firstOpTimestamp != null) {
-        if (firstOpTimestamp < cutoffTime) {
-          logger.debug(
-            { project_id, firstOpTimestamp, cutoffTime },
-            'flushing old project'
-          )
-          return UpdatesProcessor.processUpdatesForProject(
-            project_id,
-            (
-              err // always clear the flush marker after processing the project
-            ) =>
-              RedisManager.clearFirstOpTimestamp(project_id, function (e) {
-                if (e != null) {
-                  logger.error(
-                    { project_id, flushErr: e },
-                    'failed to clear flush marker'
-                  )
-                }
-                if (err) {
-                  OError.tag(err)
-                }
-                return callback(err)
-              })
-          ) // return the original error from processUpdatesFromProject
-        } else {
-          return callback()
-        }
+      // In the normal case, the flush marker will be set with the
+      // timestamp of the oldest operation in the queue by docupdater.
+      // If the marker is not set for any reason, we flush it anyway
+      // for safety.
+      if (!firstOpTimestamp || firstOpTimestamp < cutoffTime) {
+        logger.debug(
+          { project_id, firstOpTimestamp, cutoffTime },
+          'flushing old project'
+        )
+        return UpdatesProcessor.processUpdatesForProject(project_id, callback)
       } else {
-        return RedisManager.setFirstOpTimestamp(project_id, callback)
+        return callback()
       }
     }
   )
diff --git a/services/project-history/test/acceptance/js/FlushManagerTests.js b/services/project-history/test/acceptance/js/FlushManagerTests.js
index 15e60b2ae1..c25012bc9d 100644
--- a/services/project-history/test/acceptance/js/FlushManagerTests.js
+++ b/services/project-history/test/acceptance/js/FlushManagerTests.js
@@ -209,7 +209,7 @@ describe('Flushing old queues', function () {
         )
       })
 
-      it('sets the timestamp and does not flush the project history queue', function (done) {
+      it('flushes the project history queue anyway', function (done) {
         request.post(
           {
             url: `http://localhost:3054/flush/old?maxAge=${3 * 3600}`,
@@ -220,8 +220,8 @@ describe('Flushing old queues', function () {
             }
             expect(res.statusCode).to.equal(200)
             assert(
-              !this.flushCall.isDone(),
-              'did not make calls to history service to store updates'
+              this.flushCall.isDone(),
+              'made calls to history service to store updates'
             )
             ProjectHistoryClient.getFirstOpTimestamp(
               this.projectId,
@@ -229,10 +229,7 @@ describe('Flushing old queues', function () {
                 if (err) {
                   return done(err)
                 }
-                expect(parseInt(result, 10)).to.be.within(
-                  this.startDate,
-                  Date.now()
-                )
+                expect(result).to.be.null
                 done()
               }
             )