I'm sometimes getting an invalid json reply from `getwalletinfo` when rescanning is in progress.

The invalid part is this: `"scanning":{"duration":19,"progress":}}` (no value for `progress`).

I can't reliably reproduce this, but I did manage to run into this 3 times now (once every 10-20 attempts or so).

I'm running v0.20.0 and testing against a regtest instance. This happens while doing a batched `importmulti` of 2000 addresses (none of which have history).
{
        CMutableTransaction tx1 {*this->tx};
        CMutableTransaction tx2 {*_tx.tx};
        for (auto& txin : tx1.vin) txin.scriptSig = CScript();
        for (auto& txin : tx2.vin) txin.scriptSig = CScript();
        return CTransaction(tx1) == CTransaction(tx2);
}
void CWallet::ResendWalletTransactions()
{
    
    
    if (!chain().isReadyToBroadcast()) return;
    
    
    if (GetTime() < nNextResend || !fBroadcastTransactions) return;
    bool fFirst = (nNextResend == 0);
    
    nNextResend = GetTime() + (12 * 60 * 60) + GetRand(24 * 60 * 60);
    if (fFirst) return;