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.
const auto it = mapWallet.find(txid);
    if (it == mapWallet.end())
        return result;
    const CWalletTx& wtx = it->second;
    stdpair<TxSpendsconst_iterator, TxSpendsconst_iterator> range;
    for (const CTxIn& txin  wtx.tx->vin)
    {
        if (mapTxSpends.count(txin.prevout) <= 1)
            continue;  // N
        range = mapTxSpends.equal_range(txin.prevout);
        for (TxSpendsconst_iterator _it = range.first; _it != range.second; ++_it)
            result.insert(_it->second);
    }
    return result;
}
bool CWalletHasWalletSpend(const CTransactionRef& tx) const
{
    AssertLockHeld(cs_);
    const uint256& txid = tx->GetHash();
    for (unsigned int i = 0; i < tx->vout.size(); ++i) {
        if (IsS(COutPoint(txid, i))) {
            return true;
        }
    }
    return false;
}
void CWalletFlush()
{
    GetDatabase().Flush();
}