"Señor, ¡trabaje en esta oficina!"
Translation:Sir, work in this office!
So, is 'trabaje' a command form? Because 'He works in..." would be "Él trabaja en...". Correct?
So the hover suggestion is right then, in order to make sense it literally means "Sir, you are working in this office!" (get on with it).
In this example, ¨Sir you work in this office¨ is wrong because you are giving a command. So just: Sir, work in this office. The hover over, I think could be made more clear, or some explanation on how to give a command in the Spanish language, instead of just throwing it in there. This should help. https://www.spanishdict.com/guide/affirmative-informal-tu-commands
My understanding is that your alternate translation of the Duolingo exercise is also a correct translation of the imperative mood. Well done!
Now there are two different opposing opinions about this issue that are posted in this forum thread.
Yes and No. In this case no, it´s a command, but you´re right that trabaje is the 1st and 3rd singular subjective form of the verb trabajar.