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).
{
    
    if (!pwallet->GetBroadcastTransactions()) return false;
    
    if (isAbandoned()) return false;
    
    
    if (IsCoinBase()) return false;
    
    if (GetDepthInMainChain() != 0) return false;
    
    pwallet->WalletLogPrintf("Submitting wtx %s to mempool for relay\n", GetHash().ToString());
    
    
    
    
    
    
    
    
    
    bool ret = pwallet->chain().broadcastTransaction(tx, pwallet->m_default_max_tx_fee, relay, err_string);
    fInMempool |= ret;
    return ret;
}
std::set<uint256> CWalletTx::GetConflicts() const