doctrine deleting has to be done twice

I have the following DB structure and relations:

Posts -> OneToMany,cascade={"persist"} -> Replies -> OneToMany,cascade={"persist"} -> Files entities + files on disk -> event to delete files entities

Posts -> OneToMany,cascade={"persist"} -> Files entities + files on disk -> event to delete files entities

The thing about files is:

• deleting files entity (from application) deletes file on disk
• deleting file on disk (from file manager) fires an event deleting files entity

What I need is if a post is deleted, it cascades all the way to deleting replies, file entities and its files on disk. The chain of events is:

1. page controller:

post->remove();

2. Post class:

remove()
{
    PostFile::deleteFiles($this);
    Reply::deleteFiles($this);
    $em->remove($this);
    $em->flush();
}

3. PostFile:

deleteFiles($post)
{
    $files = $post->getFiles()->toArray();
    foreach ($files as $file) {
        $f->delete();
    }
}

4. Reply:

deleteFiles($post)
{
    $replies = $post->getReplies()->toArray();
    foreach ($replies as $reply) {
        if ($reply) {
            ReplyFile::deleteFiles($reply);
        }
    }
}

5. ReplyFile:

deleteFiles($reply)
{
    $files = $reply->getFiles()->toArray();
    foreach ($files as $file) {
        $f->delete();
    }
}

6. File deletion event:

Events::addListener('on_file_delete', function($event) {
    $f = $event->getFileObject();
    $fid = $file->getFileID();
    $fpf = PostFile::getByFileID($fid);
    $fpf->delete();
    $fpmf = ReplyFile::getByFileID($fid);
    $fpmf->delete();
});

Everything down the chain works fine, e.g. everything gets deleted, except for the post itself which doesn't get deleted, it has to be deleted twice. Why can that be?

Changing OneToMany,cascade={"persist"} to OneToMany,cascade={"remove"} seemed to have fixed it, now everything gets deleted on first try