Company lawyer gives a bizarre assessment

My company employs a number of foreign nationals with a variety of work permits (blue card, 18a, family reunification etc.).

According to this person none of the foreign nationals are allowed to go to a Schengen country for short business trips, conferences and trainings. Even within Germany this is supposedly not allowed other than strictly at our company address/premises.

I find this assessment bizarre because short temporary trips to other Schengen countries, be it for tourism or business is allowed as long as you have the appropriate residence title.

Is there something I am missing here? There are many sources but here is an example clarifying this for Blue Card holders at least.