**How to reproduce**
Clickhouse version 21.5

```
cat /etc/clickhouse-server/users.xml
<?xml version="1.0"?>
<yandex>
    <!-- Profiles of settings. -->
    <profiles>
        <!-- Default settings. -->
        <default>
            <data_type_default_nullable>1</data_type_default_nullable>
            <load_balancing>random</load_balancing>
        </default>
....

2021.04.04 01:23:42.453678 [ 29048 ] {} <Error> Application: DB::Exception: Nested type Array(UInt64) cannot be inside Nullable type: Cannot attach table `system`.`crash_log` from metadata file /var/lib/clickhouse/metadata/system/crash_log.sql from query ATTACH TABLE system.crash_log (`event_date` Date, `event_time` DateTime, `timestamp_ns` UInt64, `signal` Int32, `thread_id` UInt64, `query_id` String, `trace` Array(UInt64), `trace_full` Array(String), `version` String, `revision` UInt32, `build_id` String) ENGINE = MergeTree ORDER BY (event_date, event_time) SETTINGS index_granularity = 8192: while loading database `system` from path /var/lib/clickhouse/metadata/system
```
getContext()->checkAccess(AccessType::SYSTEM_SHUTDOWN);
            if (kill(0, SIGTERM))
                throwFromErrno("System call kill(0, SIGTERM) failed", ErrorCodes::CANNOT_KILL);
            break;
        }
        case Type::KILL:
        {
            getContext()->checkAccess(AccessType::SYSTEM_SHUTDOWN);
            
            
            LOG_INFO(log, "Exit immediately as the SYSTEM KILL command has been issued.");
            _exit(128 + SIGKILL);
            
        }
        case Type::SUSPEND:
        {
            auto command = fmt::format("kill -STOP {0} && sleep {1} && kill -CONT {0}", getpid(), query.seconds);
            LOG_DEBUG(log, "Will run {}", command);
            auto res = ShellCommand::execute(command);
            res->in.close();
            WriteBufferFromOwnString out;
            copyData(res->out, out);
            copyData(res->err, out);
            if (!out.str().empty())
                LOG_DEBUG(log, "The command returned output: {}", command, out.str());
            res->wait();
            break;
        }
        case Type::DROP_DNS_CACHE:
        {