### 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_
{
    WalletBatch batch(m_storage.GetDatabase());
    for (const auto& entry : privkey_map) {
        const CKey& key = entry.second;
        CPubKey pubkey = key.GetPubKey();
        const CKeyID& id = entry.first;
        assert(key.VerifyPubKey(pubkey));
        
        if (HaveKey(id)) {
            WalletLogPrintf("Already have key with pubkey %s, skipping\n", HexStr(pubkey));
            continue;
        }
        mapKeyMetadata[id].nCreateTime = timestamp;
        
        if (!AddKeyPubKeyWithDB(batch, key, pubkey)) {
            return false;
        }
        UpdateTimeFirstKey(timestamp);
    }
    return true;
}
bool LegacyScriptPubKeyMan::ImportPubKeys(const std::vector<CKeyID>& ordered_pubkeys, const std::map<CKeyID, CPubKey>& pubkey_map, const std::map<CKeyID, std::pair<CPubKey, KeyOriginInfo>>& key_origins, const bool add_keypool, const bool internal, const int64_t timestamp)