### 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_
{
    bool a_check = (a.size() > 9 && a[a.size() - 9] == '#');
    bool b_check = (b.size() > 9 && b[b.size() - 9] == '#');
    if (a_check != b_check) {
        if (a_check) a = a.substr(0, a.size() - 9);
        if (b_check) b = b.substr(0, b.size() - 9);
    }
    return a == b;
}
std::string UseHInsteadOfApostrophe(const std::string& desc)
{
    std::string ret = desc;
    while (true) {
        auto it = ret.find('\'');
        if (it == std::string::npos) break;
        ret[it] = 'h';
    }
    
    
    if (GetDescriptorChecksum(ret) == "") {
        ret = ret.substr(0, desc.size() - 9);
        ret += std::string("#") + GetDescriptorChecksum(ret);
    }
    return ret;
}
static size_t CountXpubs(const std::string& desc)