`PhabricatorApplicationTransactionCommentView` performs `$uri = id(new PhutilURI('/login/'))->replaceQueryParam('next', (string)$this->getRequestURI())` but the constructor call in `PhabricatorEditEngine` does not set any `RequestURI` so the `Log In to Comment` button at the bottom of an object view does not redirect back to the object URI after login.
Thus pass a `RequestURI` to `PhabricatorApplicationTransactionCommentView` in the constructor call in `PhabricatorEditEngine`.