Note that in Arabic there are no vowels. Also note that it's not the common "good morning" (Sabah Al-khair), but a rarer term: one word, 6 letters, no vowels. The equivalent in english would be "gdmrng".
It is a shortened form though, and is equivalent to "Morning!"
Maybe the translation algorithm confused "Yisbah-hum" (good morning) with "Yitbah-hum" (Kill them)?
One of the problems people face with learning Arabic is that weak vowels are implicit by nature and you need to know them by heart in order to read the words properly.