### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current behaviour

I randomly encountered this by loading a wallet created from master with an older version. I could trace it down to bd13dc2f46ea10302a928fcf0f53b7aed77ad260 (#26076), but I don't know descriptor wallets enough to understand what's going on (cc @Sjors @achow101).

### Expected behaviour

`bitcoind` starts, or at least tells me to use a later version if #26076 was a breaking change instead of corrupting `wallet.dat`.

### Steps to reproduce

(master, clean chain): 
`createwallet -regtest ""`
(v25.0rc2):
first `bitcoind -regtest` succeeds
then stop and restart the node: The second `bitcoind -regtest` leads to an InitError:
`Error: Error: Unable to expand wallet descriptor from cache`
now, the wallet cannot be loaded by either version.

### Relevant log output

_No response_

### How did you obtain Bitcoin Core

Compiled from source

### What version of Bitcoin Core are you using?

v25.0rc2 / master

### Operating system and version

Ubuntu

### Machine specifications

_No response_
if (internal) {
            DeriveExtKey(chainChildKey, hd_chain.nInternalChainCounter | BIP32_HARDENED_KEY_LIMIT, childKey);
            metadata.hdKeypath = "m/0'/1'/" + ToString(hd_chain.nInternalChainCounter) + "'";
            metadata.key_origin.path.push_back(0 | BIP32_HARDENED_KEY_LIMIT);
            metadata.key_origin.path.push_back(1 | BIP32_HARDENED_KEY_LIMIT);
            metadata.key_origin.path.push_back(hd_chain.nInternalChainCounter | BIP32_HARDENED_KEY_LIMIT);
            hd_chain.nInternalChainCounter++;
        }
        else {
            DeriveExtKey(chainChildKey, hd_chain.nExternalChainCounter | BIP32_HARDENED_KEY_LIMIT, childKey);
            metadata.hdKeypath = "m/0'/0'/" + ToString(hd_chain.nExternalChainCounter) + "'";
            metadata.key_origin.path.push_back(0 | BIP32_HARDENED_KEY_LIMIT);
            metadata.key_origin.path.push_back(0 | BIP32_HARDENED_KEY_LIMIT);
            metadata.key_origin.path.push_back(hd_chain.nExternalChainCounter | BIP32_HARDENED_KEY_LIMIT);
            hd_chain.nExternalChainCounter++;
        }
    } while (HaveKey(childKey.key.GetPubKey().GetID()));
    secret = childKey.key;
    metadata.hd_seed_id = hd_chain.seed_id;
    CKeyID master_id = masterKey.key.GetPubKey().GetID();
    std::copy(master_id.begin(), master_id.begin() + 4, metadata.key_origin.fingerprint);
    metadata.has_key_origin = true;
    
    if (hd_chain.seed_id == m_hd_chain.seed_id && !batch.WriteHDChain(hd_chain))
        throw std::runtime_error(std::string(__func__) + ": writing HD chain model failed");
}
void LegacyScriptPubKeyMan::LoadKeyPool(int64_t nIndex, const CKeyPool &keypool)