Day by day I discover a number of (like 3) quantity=1 sat invoices in my lnd’s listinvoices. These invoices have an empty payment_request, a zero expiry, an empty description_hash and so on. Is this type of a well being examine?

Instance (confidential stuff repl by xxxx):

{
            "memo": "",
            "r_preimage": "xxxx=",
            "r_hash": "xxxx=",
            "worth": "1",
            "value_msat": "1000",
            "settled": true,
            "creation_date": "xxxx",
            "settle_date": "xxxx",
            "payment_request": "",
            "description_hash": "",
            "expiry": "0",
            "fallback_addr": "",
            "cltv_expiry": "13",
            "route_hints": [],
            "non-public": false,
            "add_index": "xxxx",
            "settle_index": "xxxx",
            "amt_paid": "1000",
            "amt_paid_sat": "1",
            "amt_paid_msat": "1000",
            "state": "SETTLED",
            "htlcs": [
                {
                    "chan_id": "xxxx",
                    "htlc_index": "199",
                    "amt_msat": "1000",
                    "accept_height": xxxx,
                    "accept_time": "xxxx",
                    "resolve_time": "xxxx",
                    "expiry_height": xxxx,
                    "state": "SETTLED",
                    "custom_records": {
                        "xxx": "xxxx",
                        "xxx": "xxxx=",
                        "xxx": "xxxx"
                    },
                    "mpp_total_amt_msat": "0",
                    "amp": null
                }
            ],
            "options": {
                "9": {
                    "identify": "tlv-onion",
                    "is_required": false,
                    "is_known": true
                }
            },
            "is_keysend": true,
            "payment_addr": "xxx=",
            "is_amp": false,
            "amp_invoice_state": {}
        }