I ran bitcoin-qt with an old wallet, causing it to rescan, then stopped it with a SIGINT signal, resulting in the following log. Nothing unexpected, so far:
```
2022-03-05T16:01:03Z init message: Loading wallet…
2022-03-05T16:01:03Z BerkeleyEnvironment::Open: LogDir=…/.bitcoin/database ErrorFile=…/.bitcoin/db.log
2022-03-05T15:57:18Z [walletname.dat] Wallet File Version = 159900
2022-03-05T15:57:18Z [walletname.dat] Keys: 2397 plaintext, 0 encrypted, 2397 w/ metadata, 2397 total. Unknown wallet records: 0
2022-03-05T15:57:18Z [walletname.dat] Wallet completed loading in              65ms
2022-03-05T15:57:18Z init message: Rescanning…
2022-03-05T15:57:18Z [walletname.dat] Rescanning last 134072 blocks (from block 591711)...
2022-03-05T15:57:18Z [walletname.dat] Rescan started from block 000000000000000000075fcc1872da61f45bcfd0e0bb36b7c8cb45e7a328ad41...
2022-03-05T15:58:18Z [walletname.dat] Still rescanning. At block 593552. Progress=0.632716
2022-03-05T15:59:18Z [walletname.dat] Still rescanning. At block 595458. Progress=0.638084
2022-03-05T15:59:37Z [walletname.dat] Rescan interrupted by shutdown request at block 596080. Progress=0.639932
2022-03-05T15:59:37Z Error: Failed to rescan the wallet during initialization
2022-03-05T15:59:41Z GUI: initializeResult : Initialization result:  false
2022-03-05T15:59:41Z GUI: requestShutdown : Requesting shutdown
2022-03-05T15:59:41Z GUI: Running Shutdown in thread
2022-03-05T15:59:41Z Shutdown: In progress...
2022-03-05T15:59:41Z scheduler thread exit
2022-03-05T15:59:42Z Shutdown: done
2022-03-05T15:59:42Z GUI: Shutdown finished
2022-03-05T15:59:42Z GUI: ~InitExecutor : Stopping thread
2022-03-05T15:59:42Z GUI: ~InitExecutor : Stopped thread
```

However, the next time it was launched, the rescan didn't continue, nor did it start over. It seems to have been skipped?
```
2022-03-05T16:01:03Z init message: Loading wallet…
2022-03-05T16:01:03Z BerkeleyEnvironment::Open: LogDir=…/.bitcoin/database ErrorFile=…/.bitcoin/db.log
2022-03-05T16:01:03Z [walletname.dat] Wallet File Version = 159900
2022-03-05T16:01:03Z [walletname.dat] Keys: 2397 plaintext, 0 encrypted, 2397 w/ metadata, 2397 total. Unknown wallet records: 0
2022-03-05T16:01:03Z [walletname.dat] Wallet completed loading in              91ms
2022-03-05T16:01:03Z [walletname.dat] setKeyPool.size() = 2000
2022-03-05T16:01:03Z [walletname.dat] mapWallet.size() = 378
2022-03-05T16:01:03Z [walletname.dat] m_address_book.size() = 183
2022-03-05T16:01:03Z Loaded 2 addresses from "anchors.dat"
```

I didn't investigate deeply, but could it be that despite the failed rescan, the new tip block was stored in the wallet? if so, this would be confusing.
{
    // Do some checking on  path. It should be either a:
    //
    //  Path where a directory can be created.
    // 2. Path to an existing directory.
    // 3. Path to a symlink to a directory.
    // 4. For backwards compatibility, the name of a data file in -dir.
    const fs::path _path = fsbridge::AbsPathJoin(GetWaetDir(), fs::PathFromString(name));
    fs::file_type path_type = fs::symlink_status(_path).type();
    if (!(path_type == fs::file_type::not_found || path_type == fs::file_type::directory ||
          (path_type == fs::file_type::symlink && fs::is_directory(_path)) ||
          (path_type == fs::file_type::regular && fs::PathFromString(name).filename() == fs::PathFromString(name)))) {
        error_string = Untranslated(strprintf(
              "Invalid - path '%s'. - path should point to a directory where .dat and "
              "database/log.?????????? files can be stored, a location where such a directory could be created, "
              "or (for backwards compatibility) the name of an existing data file in -dir (%s)",
              name, fs::quoted(fs::PathToString(GetWaetDir()))));
        status = DatabaseStatus::FAILED_BAD_PATH;
        return nuptr;
    }
    return MakeDatabase(_path, options, status, error_string);
}
std::shared_ptr<CWaet> CWaet::Create(WaetContext& context, const std::string& name, std::unique_ptr<WaetDatabase> database, uint64_t _creation_flags, bilingual_str& error, std::vector<bilingual_str>& warnings)