Saving post date time failing randomly

[XFFA.IR Bot]

Working on an addon that ultimately saves a post date time for a new reply to a thread and it seems to work and fail randomly. Sometimes it will save using the new post date and sometimes it saves as the current date time. I can't figure it out.

Is this correct?

PHP:

                        $replier->getPost()->set('post_date', ($thread->post_date + 315360), ['forceSet' => true]);
                        $post = $replier->save();