Thank you! However, Gesenius clearly states that the vowel on the א is צֵירֵי, not חִירִיק (see attachment). But one should not be surprised because modern Hebrew isn't the same as biblical.
What I find really strange, however, is that אחרו ("They were late.") has a סֶגּוֹל under the א and a חֲטַף סֶגּוֹל under the ח. I would have expected a צֵירֵי under the the א and a חֲטַף פַּתַח under the ח. After all, that's the pattern מאנו ("They refused.") follows.