While checking #16661 I stumbled upon what seems to be a lifetime issue in `ReleaseWallet(CWallet* wallet)` (`wallet.cpp`).

https://github.com/bitcoin/bitcoin/blob/fa6431055abfacea4f72ef11d061c7c755de327a/src/wallet/wallet.cpp#L107-L111

After `delete wallet;` the pointer is invalid and shouldn't be used like in the call `g_unloading_wallet_set.erase(wallet)`.

The code was introduced in #14941 which was merged into `master` on January 15, 2019.

In addition to fixing this specific instance it might be worth thinking about how we can use static analysis to automatically catch this class of issues going forward :-)
{
    WalletBatch batch(*database);
    for (const auto& entry : key_origins) {
        AddKeyOriginWithDB(batch, entry.second.first, entry.second.second);
    }
    for (const CKeyID& id : ordered_pubkeys) {
        auto entry = pubkey_map.find(id);
        if (entry == pubkey_map.end()) {
            continue;
        }
        const CPubKey& pubkey = entry->second;
        CPubKey temp;
        if (GetPubKey(id, temp)) {
            
            WalletLogPrintf("Already have pubkey %s, skipping\n", HexStr(temp));
            continue;
        }
        if (!AddWatchOnlyWithDB(batch, GetScriptForRawPubKey(pubkey), timestamp)) {
            return false;
        }
        mapKeyMetadata[id].nCreateTime = timestamp;
        
        if (add_keypool) {
            AddKeypoolPubkeyWithDB(pubkey, internal, batch);
            NotifyCanGetAddressesChanged();
        }
    }
    return true;
}
bool CWallet::ImportScriptPubKeys(const std::string& label, const std::set<CScript>& script_pub_keys, const bool have_solving_data, const bool apply_label, const int64_t timestamp)