Espresso Test Number Only Field Special Characters Showing Up As Numbers

I'm trying to test that a text field in an android app only accepts numbers and no letters or special characters. However, when I run the piece of code below on my OnePlusX the special characters get inputted as numbers! But when I run it on a Nexus 5, it behaves as expected with no values inputted.

This is nuts!

Any ideas why?

@Test
public void noLoginSession_inputSpecialCharsIntoTelephone_specialCharsIgnored() {
    clearFields();
    onView(withId(R.id.login_cell_number)).perform(typeText("!@#$%^&*()-_=+")).check(matches(withText("")));
}