After commit ccd85b57af60d7034db372b9501d059fbc5941e4 I can no longer open my wallet without warnings.

![Screenshot from 2020-05-22 10-45-35](https://user-images.githubusercontent.com/6399679/82679920-9704a180-9c19-11ea-8f55-4c935ced8fe2.png)

```
Warning: Error reading /home/marco/.bitcoin/regtest/wallet.dat! All keys read correctly, but transaction data or address book entries might be missing or incorrect.

uint256 desc_id;
            uint32_t key_exp_index;
            uint32_t der_index;
            ssKey >> desc_id;
            ssKey >> key_exp_index;
            
            try
            {
                ssKey >> der_index;
                parent = false;
            }
            catch (...) {}
            std::vector<unsigned char> ser_xpub(BIP32_EXTKEY_SIZE);
            ssValue >> ser_xpub;
            CExtPubKey xpub;
            xpub.Decode(ser_xpub.data());
            if (wss.m_descriptor_caches.count(desc_id)) {
                wss.m_descriptor_caches[desc_id] = DescriptorCache();
            }
            if (parent) {
                wss.m_descriptor_caches[desc_id].CacheParentExtPubKey(key_exp_index, xpub);
            } else {
                wss.m_descriptor_caches[desc_id].CacheDerivedExtPubKey(key_exp_index, der_index, xpub);
            }
        } else if (strType == DBKeys::WALLETDESCRIPTORKEY) {
            uint256 desc_id;
            CPubKey pubkey;
            ssKey >> desc_id;
            ssKey >> pubkey;
            if (!pubkey.IsValid())