**How to reproduce**
Clickhouse server 20.13.1.5273
```
CREATE TABLE default.test
(
`key` UInt32,
`ts` DateTime CODEC(DoubleDelta, LZ4),
`db_time` DateTime DEFAULT now() COMMENT 'spout-ignore' CODEC(DoubleDelta, LZ4)
)
ENGINE = MergeTree
PARTITION BY toStartOfTenMinutes(db_time)
ORDER BY (key, ts)
TTL db_time + toIntervalHour(3)
SETTINGS index_granularity = 8192, merge_with_ttl_timeout = 3600, min_rows_for_compact_part = 1000000, min_bytes_for_compact_part = 200000000, in_memory_parts_enable_wal = 0;


INSERT INTO test(key, ts) SELECT number % 1000, now() + intDiv(number,1000) FROM numbers(500);

SELECT * FROM test;
500 rows in set. Elapsed: 0.003 sec.

DETACH TABLE test;

ATTACH TABLE test;

SELECT * FROM test;

0 rows in set. Elapsed: 0.002 sec.
```

**Expected behavior**
Clickhouse would flush parts on disk.
{
    String mutation_file_name;
    Int64 version = startMutation(commands, mutation_file_name);
    if (query_context->getSettingsRef().mutations_sync > 0)
        waitForMutation(version, mutation_file_name);
}
std::optional<MergeTreeMutationStatus> StorageMergeTree::getIncompleteMutationsStatus(Int64 mutation_version, std::set<String> * mutation_ids) const
{
    std::unique_lock lock(currently_processing_in_background_mutex);
    auto current_mutation_it = current_mutations_by_version.find(mutation_version);
    
    if (current_mutation_it == current_mutations_by_version.end())
        return {};
    MergeTreeMutationStatus result{.is_done = false};
    const auto & mutation_entry = current_mutation_it->second;
    auto data_parts = getDataPartsVector();
    for (const auto & data_part : data_parts)
    {
        Int64 data_version = getUpdatedDataVersion(data_part, lock);
        if (data_version < mutation_version)
        {
            if (!mutation_entry.latest_fail_reason.empty())