Why does IBuildResultContribution.getStatus() return ERROR when the JUnit test has passed?

I have code that does something like this:

        List<IBuildResultContribution> allTestSuites = new ArrayList<IBuildResultContribution>();
        IBuildResultContribution[] testSuites = buildClient.getBuildResultContributions(result, IJUnitTestSuiteContribution.EXTENDED_CONTRIBUTION_TYPE_ID,
                                                                                        monitor);
        allTestSuites.addAll(Arrays.asList(testSuites));

        for (IBuildResultContribution brc : allTestSuites) {
              ....
                    // Check that the test suite passed
                    if (!BuildStatus.OK.equals(brc.getStatus())) { // etc

When I visually look at the build result in the RTC UI, I see that all tests have passed. They are green. The log files also indicate that no errors or failures occurred.

However, the "brc.getStatus()" call returns ERROR, not OK. Why could this be happening? Again, the build is completely green. No errors or failures--particularly the JUnit test suite that the "brc" object represents.