Invalid Fee value for failed swap event

Midgard could not get sync with Thornode because of the following event. (pool is updated but error raised in swap event.)

{
        "id": "10",
        "height": "120",
        "type": "refund",
        "in_tx": {
            "id": "3598C001619FC1423A0BCA498573A23F540B50015C902FB5B160D9DF4BF86028",
            "chain": "BNB",
            "from_address": "tbnb1erds50nhzt0y4axp4uvq3fh8wed2m4dfycav58",
            "to_address": "tbnb1ma9367eaj7zf737pnfnxhe7u37af2tl8mttanz",
            "coins": [
                {
                    "asset": "BNB.LOK-3C0",
                    "amount": "10000000"
                }
            ],
            "gas": [
                {
                    "asset": "BNB.BNB",
                    "amount": "37500"
                }
            ],
            "memo": "SWAP:FTM-585::"
        },
        "out_txs": null,
        "gas": null,
        "event": {
            "code": 110,
            "reason": "output RUNE (13605442) is not enough to pay transaction fee"
        },
        "status": "Refund"
    }