### 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_
pwallet->GetOrCreateLegacyScriptPubKeyMan()->LoadScriptMetadata(CScriptID(script), keyMeta);
        return DBErrors::LOAD_OK;
    });
    result = std::max(result, watch_meta_res.m_result);
    
    LoadResult pool_res = LoadRecords(pwallet, batch, DBKeys::POOL,
        [] (CWallet* pwallet, DataStream& key, CDataStream& value, std::string& err) {
        int64_t nIndex;
        key >> nIndex;
        CKeyPool keypool;
        value >> keypool;
        pwallet->GetOrCreateLegacyScriptPubKeyMan()->LoadKeyPool(nIndex, keypool);
        return DBErrors::LOAD_OK;
    });
    result = std::max(result, pool_res.m_result);
    
    
    
    
    
    LoadResult default_key_res = LoadRecords(pwallet, batch, DBKeys::DEFAULTKEY,
        [] (CWallet* pwallet, DataStream& key, CDataStream& value, std::string& err) {
        CPubKey default_pubkey;
        try {
            value >> default_pubkey;
        } catch (const std::exception& e) {
            err = e.what();
            return DBErrors::CORRUPT;
        }
        if (!default_pubkey.IsValid()) {