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).
{
    return IsChange(txout.scriptPubKey);
}
bool CWallet::IsChange(const CScript& script) const
{
    
    
    
    
    
    
    
    AssertLockHeld(cs_wallet);
    if (IsMine(script))
    {
        CTxDestination address;
        if (!ExtractDestination(script, address))
            return true;
        if (!FindAddressBookEntry(address)) {
            return true;
        }
    }
    return false;
}
CAmount CWallet::GetChange(const CTxOut& txout) const