### 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_
{
        assert(m_in);
        CPubKey pubkey(begin, end);
        if (pubkey.IsValid()) {
            Key key = m_keys.size();
            m_keys.push_back(InferPubkey(pubkey, ParseScriptContext::P2WSH, *m_in));
            return key;
        }
        return {};
    }
    template<typename I> std::optional<Key> FromPKHBytes(I begin, I end) const
    {
        assert(end - begin == 20);
        assert(m_in);
        uint160 hash;
        std::copy(begin, end, hash.begin());
        CKeyID keyid(hash);
        CPubKey pubkey;
        if (m_in->GetPubKey(keyid, pubkey)) {
            Key key = m_keys.size();
            m_keys.push_back(InferPubkey(pubkey, ParseScriptContext::P2WSH, *m_in));
            return key;
        }
        return {};
    }
};
std::unique_ptr<DescriptorImpl> ParseScript(uint32_t& key_exp_index, Span<const char>& sp, ParseScriptContext ctx, FlatSigningProvider& out, std::string& error)