ADDITIONAL SYSTEM INFORMATION :
$ uname -a
Linux gonzo 5.10.0-8-amd64 #1 SMP Debian 5.10.46-4 (2021-08-03) x86_64 GNU/Linux
$ java -version
openjdk version "17" 2021-09-14
OpenJDK Runtime Environment (build 17+35-Debian-1)
OpenJDK 64-Bit Server VM (build 17+35-Debian-1, mixed mode, sharing)

A DESCRIPTION OF THE PROBLEM :
Name of timezone UTC in locale 'zh-MO' according to JDK is 協調世界時間. However, if an unrelated code (requesting the name in a different, though related, locale) is executed first, name changes to 世界標準時間.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Compile and run the short attached program like this:
$ javac test.java && java test && java test broken

Observe that the name in the same locale changes between two runs.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
zh-MO: 協調世界時間

zh-Hant-HK: 世界標準時間
zh-MO: 協調世界時間

ACTUAL -
zh-MO: 協調世界時間

zh-Hant-HK: 世界標準時間
zh-MO: 世界標準時間


---------- BEGIN SOURCE ----------
import java.time.*;
import java.time.format.*;
import java.util.*;

public class test
{
    public static void main (String[] args) throws Exception
    {
        if (args.length == 1 && args[0].equals ("broken"))
            System.out.println (utcNameIn ("zh-Hant-HK"));
        System.out.println (utcNameIn ("zh-MO"));
        System.out.println ();
    }

    protected static String utcNameIn (String locale)
    {
        return locale + ": " + DateTimeFormatter.ofPattern ("zzzz", Locale.forLanguageTag (locale)).format (ZonedDateTime.ofInstant (Instant.ofEpochSecond (0), ZoneId.of ("UTC")));
    }
}

---------- END SOURCE ----------

FREQUENCY : always