Task:test failure due to DateUtilsTest.java

I came across an issue in javarosa.When I am trying to run the build task ,it fails because the task test fails at line 298 of DateUtilsTest.java.

Basically,it is trying to assert month name ene --> new LangJanSun("es", "ene", "dom"), but receiving
ene. and dom. from below code.
String month = DateUtils.format(DateFields.of(2018, 1, 1, 10, 20, 30, 400), "%b");
assertEquals(ljs.january, month);
Is it known issue if not,can I raise a issue and corresponding PR.