Adding the test below to test__locale.py will reproduce the issue under the following conditions:
- The locale `uk_UA` is installed on your system.
- 'uk_UA': (',', '\xa0') is added to the `known_numerics` dictionary in this test file

    @unittest.skipUnless(nl_langinfo, "nl_langinfo is not available")
    def test_lc_numeric_not_char_nl_langinfo(self):
        # Test nl_langinfo against known values/
        # It should still work if there's a mismatch between
        # String & Numeric Locales
        tested = False
        for loc in candidate_locales:
            try:
                setlocale(LC_NUMERIC, loc)
            except Error:
                continue
            for li, lc in ((RADIXCHAR, "decimal_point"),
                            (THOUSEP, "thousands_sep")):
                if self.numeric_tester('nl_langinfo', nl_langinfo(li), lc, loc):
                    tested = True
        if not tested:
            self.skipTest('no suitable locales')