The failing test cases:

src/test/java/org/joda/time/TestDuration_Basics.java:470-492
public void testToPeriod_fixedZone() throws Throwable {
    DateTimeZone zone = DateTimeZone.getDefault();
    try {
        DateTimeZone.setDefault(DateTimeZone.forOffsetHours(2));
        long length =
            (4L + (3L * 7L) + (2L * 30L) + 365L) * DateTimeConstants.MILLIS_PER_DAY +
            5L * DateTimeConstants.MILLIS_PER_HOUR +
            6L * DateTimeConstants.MILLIS_PER_MINUTE +
            7L * DateTimeConstants.MILLIS_PER_SECOND + 8L;
        Duration dur = new Duration(length);
        Period test = dur.toPeriod();
        assertEquals(0, test.getYears());  // (4 + (3 * 7) + (2 * 30) + 365) == 450
        assertEquals(0, test.getMonths());
        assertEquals(0, test.getWeeks()); // <-- TC fails here
        assertEquals(0, test.getDays());
        assertEquals((450 * 24) + 5, test.getHours());
        assertEquals(6, test.getMinutes());
        assertEquals(7, test.getSeconds());
        assertEquals(8, test.getMillis());
    } finally {
        DateTimeZone.setDefault(zone);
    }
}
src/test/java/org/joda/time/TestPeriod_Constructors.java:174-197
public void testConstructor_long_fixedZone() throws Throwable {
    DateTimeZone zone = DateTimeZone.getDefault();
    try {
        DateTimeZone.setDefault(DateTimeZone.forOffsetHours(2));
        long length =
            (4L + (3L * 7L) + (2L * 30L) + 365L) * DateTimeConstants.MILLIS_PER_DAY +
            5L * DateTimeConstants.MILLIS_PER_HOUR +
            6L * DateTimeConstants.MILLIS_PER_MINUTE +
            7L * DateTimeConstants.MILLIS_PER_SECOND + 8L;
        Period test = new Period(length);
        assertEquals(PeriodType.standard(), test.getPeriodType());
        // only time fields are precise in AllType
        assertEquals(0, test.getYears());  // (4 + (3 * 7) + (2 * 30) + 365) == 450
        assertEquals(0, test.getMonths());
        assertEquals(0, test.getWeeks()); // <-- TC fails here
        assertEquals(0, test.getDays());
        assertEquals((450 * 24) + 5, test.getHours());
        assertEquals(6, test.getMinutes());
        assertEquals(7, test.getSeconds());
        assertEquals(8, test.getMillis());
    } finally {
        DateTimeZone.setDefault(zone);
    }
}

The faulty code:

Line is covered but NOT in slice
Line is covered and in slice
Line is in slice but NOT covered
src/main/java/org/joda/time/base/BasePeriod.java:221-224
protected BasePeriod(long duration) {
    this(duration, null, null);                            //<-- BUG!!
    // bug [3264409]
}

Other code:

src/test/java/org/joda/time/TestMutablePeriod_Basics.java:447-452
public void testClone() {
    MutablePeriod test = new MutablePeriod(123L);
    MutablePeriod copy = (MutablePeriod) test.clone();
    assertEquals(test.getPeriodType(), copy.getPeriodType());
    assertEquals(test, copy);
}