whereHas w/ Addtl Constraints Not Working w/ withTrashedPivots

[TCURT15]

class Post extends Model
{
    public function tags()
    {
        return $this->belongsToMany(Tag::class)->withSoftDeletes()->withTrashedPivots();
    }
}

Post::whereHas('tags'); // works as expected

Post::whereHas('tags', function ($query) {
  $query->where('tags.x', 'y');
}); // does not include trashed pivots