Mocking call chain does not work for public interface hierarchy in multiple tests

[Milbor-zz]

1.32
testng 6.9.10

when whole test class run - test1 passes, test2 fails with NPE when mocking call chain.
Passes in 1.31.
Is this bug? I don't see anything relevant in release notes.
Please see comments in code. Interface and class public visibility affects test result.

public class SpikeTest {
    @Injectable
    private SubInterface subInterface;

    @Test
    public void test1() {
        test();
    }

    @Test
    public void test2() {
        test();
    }

    private void test() {
        final String expected = "mocked";
        new Expectations() {{
            subInterface.getData().get();
            result = expected;
        }};
        final String actual = subInterface.getData().get();
        assertSame(actual, expected);
    }

    interface ParentInterface {
        Data getData();
    }

    // both tests pass with default visibility
    public interface SubInterface extends ParentInterface {
    }

    // first test fails with default visibility
    // java.lang.IllegalAccessError: tried to access class SpikeTest$Data from class $Impl_SubInterface
    public static class Data {
        String get() {
            throw new UnsupportedOperationException();
        }
    }
}