SiftingAppender don't work in logback 1.4.14

[solu-jt0907]

Below code work well in logback 1.4.7 but not in logback 1.4.14.

I wanna know the cause of this occurrence.

the development environment is in java 17

import java.text.SimpleDateFormat;
import java.util.Date;

import org.slf4j.MDC;

import ch.qos.logback.classic.Level;
import ch.qos.logback.classic.Logger;
import ch.qos.logback.classic.LoggerContext;
import ch.qos.logback.classic.encoder.PatternLayoutEncoder;
import ch.qos.logback.classic.sift.MDCBasedDiscriminator;
import ch.qos.logback.classic.sift.SiftingAppender;
import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.core.Appender;
import ch.qos.logback.core.Context;
import ch.qos.logback.core.FileAppender;
import ch.qos.logback.core.sift.AppenderFactory;
import ch.qos.logback.core.util.Duration;

public class LogbackMessageLogTest {

    private static final LoggerContext LOG_CTX = new LoggerContext();

    private static final String LOGGER_NAME = "ONLMSG";

    private static final String LOG_MDC_KEY = "logName";

    public static void main(String[] args) {
        LogbackMessageLogTest test = new LogbackMessageLogTest();
        test.test();
    }

    public void test() {

        SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmm");

        long start = System.currentTimeMillis();
        for (int i = 0; i < 100L; i++) {
            // logger

            String procTime = sdf.format(new Date(start + (i * 500L)));
            String date = procTime.substring(0, 8);
            String time = procTime.substring(8);
            String logName = date.concat("/ONLMSG_").concat(time);

            MDC.put(LOG_MDC_KEY, logName);

            Logger logger = getMessageLogger();
            logger.error("Hello {}", i + 1);
            try {
                Thread.sleep(10);
            } catch (Exception e) {
                // ignore...
            }
            MDC.clear();
        }
    }

    private Logger getMessageLogger() {

        Logger logger = LOG_CTX.exists(LOGGER_NAME);
        if (logger != null) {
            return logger;
        }

        synchronized (LogbackMessageLogTest.class) {
            logger = LOG_CTX.exists(LOGGER_NAME);
            if (logger != null) {
                return logger;
            }

            System.err.println("create logger...");

            SiftingAppender sa = new SiftingAppender();
            sa.setName(LOGGER_NAME + "SIFT");
            sa.setContext(LOG_CTX);

            MDCBasedDiscriminator discriminator = new MDCBasedDiscriminator();
            discriminator.setKey(LOG_MDC_KEY);
            discriminator.setDefaultValue(LOGGER_NAME + "_unknown");
            discriminator.start();
            sa.setDiscriminator(discriminator);
            sa.setMaxAppenderCount(10);
            sa.setTimeout(Duration.buildByMinutes(3L));

            sa.setAppenderFactory(new AppenderFactory<ILoggingEvent>() {

                @Override
                public Appender<ILoggingEvent> buildAppender(Context context, String value) {
                    String filename = "./" + value + ".log";
                    System.err.println("buildAppender " + filename);

                    FileAppender<ILoggingEvent> appender = new FileAppender<>();
                    appender.setName("ONLMSG_" + value);
                    appender.setContext(context);
                    appender.setAppend(true);
                    appender.setFile(filename);

                    PatternLayoutEncoder encoder = new PatternLayoutEncoder();
                    encoder.setContext(context);
                    encoder.setPattern("%msg%n");
                    encoder.start();

                    appender.setEncoder(encoder);
                    appender.start();
                    return appender;
                }
            });
            sa.start();

            logger = LOG_CTX.getLogger(LOGGER_NAME);
            logger.addAppender(sa);
            logger.setLevel(Level.INFO);
        }

        return logger;
    }

}