diff --git a/src/applications/transactions/editor/PhabricatorApplicationTransactionCommentEditor.php b/src/applications/transactions/editor/PhabricatorApplicationTransactionCommentEditor.php
index 2728e4cfed..c6d9081958 100644
--- a/src/applications/transactions/editor/PhabricatorApplicationTransactionCommentEditor.php
+++ b/src/applications/transactions/editor/PhabricatorApplicationTransactionCommentEditor.php
@@ -1,155 +1,159 @@
 <?php
 
 final class PhabricatorApplicationTransactionCommentEditor
   extends PhabricatorEditor {
 
   private $contentSource;
   private $actingAsPHID;
 
   public function setActingAsPHID($acting_as_phid) {
     $this->actingAsPHID = $acting_as_phid;
     return $this;
   }
 
   public function getActingAsPHID() {
     if ($this->actingAsPHID) {
       return $this->actingAsPHID;
     }
     return $this->getActor()->getPHID();
   }
 
   public function setContentSource(PhabricatorContentSource $content_source) {
     $this->contentSource = $content_source;
     return $this;
   }
 
   public function getContentSource() {
     return $this->contentSource;
   }
 
   /**
    * Edit a transaction's comment. This method effects the required create,
    * update or delete to set the transaction's comment to the provided comment.
    */
   public function applyEdit(
     PhabricatorApplicationTransaction $xaction,
     PhabricatorApplicationTransactionComment $comment) {
 
     $this->validateEdit($xaction, $comment);
 
     $actor = $this->requireActor();
 
     $comment->setContentSource($this->getContentSource());
     $comment->setAuthorPHID($this->getActingAsPHID());
 
     // TODO: This needs to be more sophisticated once we have meta-policies.
     $comment->setViewPolicy(PhabricatorPolicies::POLICY_PUBLIC);
     $comment->setEditPolicy($this->getActingAsPHID());
 
     $file_phids = PhabricatorMarkupEngine::extractFilePHIDsFromEmbeddedFiles(
       $actor,
       array(
         $comment->getContent(),
       ));
 
     $xaction->openTransaction();
       $xaction->beginReadLocking();
         if ($xaction->getID()) {
           $xaction->reload();
         }
 
         $new_version = $xaction->getCommentVersion() + 1;
 
         $comment->setCommentVersion($new_version);
         $comment->setTransactionPHID($xaction->getPHID());
         $comment->save();
 
         $xaction->setCommentVersion($new_version);
         $xaction->setCommentPHID($comment->getPHID());
         $xaction->setViewPolicy($comment->getViewPolicy());
         $xaction->setEditPolicy($comment->getEditPolicy());
         $xaction->save();
         $xaction->attachComment($comment);
 
-        $object = id(new PhabricatorObjectQuery())
-          ->withPHIDs(array($xaction->getObjectPHID()))
-          ->setViewer($this->getActor())
-          ->executeOne();
-        if ($object &&
-            $object instanceof PhabricatorApplicationTransactionInterface) {
-          $editor = $object->getApplicationTransactionEditor();
-          $editor->setActor($this->getActor());
-          $support_xactions = $editor->getExpandedSupportTransactions(
-            $object,
-            $xaction);
-          if ($support_xactions) {
-            $editor
-              ->setContentSource($this->getContentSource())
-              ->setContinueOnNoEffect(true)
-              ->applyTransactions($object, $support_xactions);
+        // For comment edits, we need to make sure there are no automagical
+        // transactions like adding mentions or projects.
+        if ($new_version > 1) {
+          $object = id(new PhabricatorObjectQuery())
+            ->withPHIDs(array($xaction->getObjectPHID()))
+            ->setViewer($this->getActor())
+            ->executeOne();
+          if ($object &&
+              $object instanceof PhabricatorApplicationTransactionInterface) {
+            $editor = $object->getApplicationTransactionEditor();
+            $editor->setActor($this->getActor());
+            $support_xactions = $editor->getExpandedSupportTransactions(
+              $object,
+              $xaction);
+            if ($support_xactions) {
+              $editor
+                ->setContentSource($this->getContentSource())
+                ->setContinueOnNoEffect(true)
+                ->applyTransactions($object, $support_xactions);
+            }
           }
         }
       $xaction->endReadLocking();
     $xaction->saveTransaction();
 
     // Add links to any files newly referenced by the edit.
     if ($file_phids) {
       $editor = new PhabricatorEdgeEditor();
       foreach ($file_phids as $file_phid) {
         $editor->addEdge(
           $xaction->getObjectPHID(),
           PhabricatorEdgeConfig::TYPE_OBJECT_HAS_FILE,
           $file_phid);
       }
       $editor->save();
     }
 
     return $this;
   }
 
   /**
    * Validate that the edit is permissible, and the actor has permission to
    * perform it.
    */
   private function validateEdit(
     PhabricatorApplicationTransaction $xaction,
     PhabricatorApplicationTransactionComment $comment) {
 
     if (!$xaction->getPHID()) {
       throw new Exception(
         'Transaction must have a PHID before calling applyEdit()!');
     }
 
     $type_comment = PhabricatorTransactions::TYPE_COMMENT;
     if ($xaction->getTransactionType() == $type_comment) {
       if ($comment->getPHID()) {
         throw new Exception(
           'Transaction comment must not yet have a PHID!');
       }
     }
 
     if (!$this->getContentSource()) {
       throw new Exception(
         'Call setContentSource() before applyEdit()!');
     }
 
     $actor = $this->requireActor();
 
     PhabricatorPolicyFilter::requireCapability(
       $actor,
       $xaction,
       PhabricatorPolicyCapability::CAN_VIEW);
 
     if ($comment->getIsRemoved() && $actor->getIsAdmin()) {
       // NOTE: Administrators can remove comments by any user, and don't need
       // to pass the edit check.
     } else {
       PhabricatorPolicyFilter::requireCapability(
         $actor,
         $xaction,
         PhabricatorPolicyCapability::CAN_EDIT);
     }
   }
 
 
 }