### 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 (!key_in.Derive(key_out, index)) {
        throw std::runtime_error("Could not derive extended key");
    }
}
void LegacyScriptPubKeyMan::DeriveNewChildKey(WalletBatch &batch, CKeyMetadata& metadata, CKey& secret, CHDChain& hd_chain, bool internal)
{
    
    CKey seed;                     
    CExtKey masterKey;             
    CExtKey accountKey;            
    CExtKey chainChildKey;         
    CExtKey childKey;              
    
    if (!GetKey(hd_chain.seed_id, seed))
        throw std::runtime_error(std::string(__func__) + ": seed not found");
    masterKey.SetSeed(seed);
    
    
    DeriveExtKey(masterKey, BIP32_HARDENED_KEY_LIMIT, accountKey);
    
    assert(internal ? m_storage.CanSupportFeature(FEATURE_HD_SPLIT) : true);
    DeriveExtKey(accountKey, BIP32_HARDENED_KEY_LIMIT+(internal ? 1 : 0), chainChildKey);
    
    do {