When a block reward is spent together with other outputs in the wallet and that block reward is later orphaned, the wallet does not show the other funds as available anymore.  Even a `-rescan` is not enough - only `-zapwallettxes` or an explicit `abandontransaction` "recovers" the funds.  I prepared a [test case](https://github.com/domob1812/bitcoin/blob/wallet-bug-invalidated-block-rewards/test/functional/wallet_bug.py) that shows this behaviour.

Is this a known issue or the expected behaviour?  While this situation is something that will presumably not occur in practice (as it requires a long reorg), I wonder if that transaction should be automatically abandoned as it seems clear it won't be able to be confirmed anymore.
mapTxSpends.insert(stdmake_pair(outpoint, wtxid));
    if (batch) {
        UnlockCoin(outpoint, batch);
    } else {
        WalletBatch temp_batch(GetDatabase());
        UnlockCoin(outpoint, &temp_batch);
    }
    stdpair<TxSpendsiterator, TxSpendsiterator> range;
    range = mapTxSpends.equal_range(outpoint);
    SyncMetaData(range);
}
void CWalletAddToSpends(const CWalletTx& wtx, WalletBatch* batch)
{
    if (wtx.IsCoinBase()) // C
        return;
    for (const CTxIn& txin  wtx.tx->vin)
        AddToSpends(txin.prevout, wtx.GetHash(), batch);
}
bool CWalletEncryptWallet(const SecureString& strWalletPassphrase)
{
    if (IsCrypted())
        return false;
    CKeyingMaterial _vMasterKey;
    _vMasterKey.resize(WALLET_CRYPTO_KEY_SIZE);
    GetStrongRandBytes(_vMasterKey);
    CMasterKey kMasterKey;
    kMasterKey.vchSalt.resize(WALLET_CRYPTO_SALT_SIZE);
    GetStrongRandBytes(kMasterKey.vchSalt);
    CCrypter crypter;
    int64_t nStartTime = GetTimeMillis();