Steps:
Test Timezone display name consistency between CLDR and Java.
Found some timezone ID's display name are incorrect by Java API.

For example, running below code:
public void TZDisplayName() {
        String tag = "en";
        Locale target = Locale.forLanguageTag(tag);
        Locale.setDefault(target);
        TimeZone testTZ = TimeZone.getTimeZone("Pacific/Bougainville");
        TimeZone.setDefault(testTZ);
        String displayName = testTZ.getDisplayName();
        System.out.println("tz displayname:" + displayName);
    }

The output of Java is "New Zealand Standard Time". But I checked CLDR en.xml, the display name should be "Papua New Guinea Time".

The same issue happens on tzid "Asia/Srednekolymsk"