### 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_
} else if (split.back() == Span{"*'"}.first(2) || split.back() == Span{"*h"}.first(2)) {
        apostrophe = split.back() == Span{"*'"}.first(2);
        split.pop_back();
        type = DeriveType::HARDENED;
    }
    if (!ParseKeyPath(split, path, apostrophe, error)) return nullptr;
    if (extkey.key.IsValid()) {
        extpubkey = extkey.Neuter();
        out.keys.emplace(extpubkey.pubkey.GetID(), extkey.key);
    }
    return std::make_unique<BIP32PubkeyProvider>(key_exp_index, extpubkey, std::move(path), type, apostrophe);
}
std::unique_ptr<PubkeyProvider> ParsePubkey(uint32_t key_exp_index, const Span<const char>& sp, ParseScriptContext ctx, FlatSigningProvider& out, std::string& error)
{
    using namespace spanparsing;
    auto origin_split = Split(sp, ']');
    if (origin_split.size() > 2) {
        error = "Multiple ']' characters found for a single pubkey";
        return nullptr;
    }
    
    bool apostrophe = false;
    if (origin_split.size() == 1) {
        return ParsePubkeyInner(key_exp_index, origin_split[0], ctx, out, apostrophe, error);
    }
    if (origin_split[0].empty() || origin_split[0][0] != '[') {
        error = strprintf("Key origin start '[ character expected but not found, got '%c' instead",
                          origin_split[0].empty() ?  ']' : origin_split[0][0]);
        return nullptr;
    }