Filtered nested reverse aggregate search

es.json

{
    "from": 0,
    "size": 6,
    "query": {
        "bool": {
            "should": [
                {
                    "bool": {
                        "filter": {
                            "bool": {
                                "must": [
                                    {
                                        "term": {
                                            "object_type": "course"
                                        }
                                    },
                                    {
                                        "bool": {
                                            "must": [
                                                {
                                                    "nested": {
                                                        "path": "course_runs",
                                                        "query": {
                                                            "bool": {
                                                                "should": [
                                                                    {
                                                                        "term": {
                                                                            "course_runs.offered_by": "OCW"
                                                                        }
                                                                    },
                                                                    {
                                                                        "range": {
                                                                            "course_runs.best_end_date": {
                                                                                "gte": "now"
                                                                            }
                                                                        }
                                                                    }
                                                                ]
                                                            }
                                                        }
                                                    }
                                                }
                                            ],
                                            "should": [
                                                {
                                                    "nested": {
                                                        "path": "course_runs",
                                                        "query": {
                                                            "range": {
                                                                "course_runs.best_start_date": {
                                                                    "to": "now"
                                                                }
                                                            }
                                                        }
                                                    }
                                                }
                                            ]
                                        }
                                    }
                                ]
                            }
                        }
                    }
                }
            ]
        }
    },
    "aggs": {
        "type": {
            "terms": {
                "field": "object_type.keyword",
                "size": 10000
            }
        },
        "platform": {
            "terms": {
                "field": "platform",
                "size": 10000
            }
        },
        "topics": {
            "terms": {
                "field": "topics",
                "size": 10000
            }
        },
        "availability": {
            "nested": {
                "path": "course_runs"
            },
            "aggs": {
                "runs": {
                    "date_range": {
                        "field": "course_runs.best_start_date",
                        "missing": "1901-01-01T00:00:00Z",
                        "keyed": false,
                        "ranges": [
                            {
                                "key": "availableNow",
                                "to": "now"
                            },
                            {
                                "key": "nextWeek",
                                "from": "now",
                                "to": "now+7d"
                            },
                            {
                                "key": "nextMonth",
                                "from": "now",
                                "to": "now+1M"
                            },
                            {
                                "key": "next3Months",
                                "from": "now",
                                "to": "now+3M"
                            },
                            {
                                "key": "next6Months",
                                "from": "now",
                                "to": "now+6M"
                            },
                            {
                                "key": "nextYear",
                                "from": "now",
                                "to": "now+12M"
                            }
                        ]
                    },
                    "aggs": {
                        "courses": {
                            "reverse_nested": {}
                        }
                    }
                }
            }
        },
        "expired": {
            "nested": {
                "path": "course_runs"
            },
            "aggs": {
                "runs": {
                    "filters": {
                        "filters": {
                            "expired": {
                                "bool": {
                                    "must": [
                                        {
                                            "nested": {
                                                "path": "course_runs",
                                                "query": {
                                                    "bool": {
                                                        "should": [
                                                            {
                                                                "term": {
                                                                    "course_runs.offered_by": "OCW"
                                                                }
                                                            },
                                                            {
                                                                "range": {
                                                                    "course_runs.best_end_date": {
                                                                        "gte": "now"
                                                                    }
                                                                }
                                                            }
                                                        ]
                                                    }
                                                }
                                            }
                                        }
                                    ],
                                    "should": [
                                        {
                                            "nested": {
                                                "path": "course_runs",
                                                "query": {
                                                    "range": {
                                                        "course_runs.best_start_date": {
                                                            "to": "now"
                                                        }
                                                    }
                                                }
                                            }
                                        }
                                    ]
                                }
                            }
                        }
                    },
                    "aggs": {
                        "courses": {
                            "reverse_nested": {}
                        }
                    }
                }
            }
        }
    }
}