Is it permissible for a traveler to shorten the prayer if the duration of the journey is undefined, and is it permissible to shorten the Maghrib prayer out of ignorance of the ruling?

A resident outside his hometown is considered a traveler if the distance is that which permits shortening prayers. Travel ceases with a stay of four full days, excluding the days of arrival and departure. So, if your stay at the company headquarters is only three days, along with two days of travel, you are considered a traveler. It is permissible to shorten the four-rak'ah prayers to two rak'ahs during travel. However, the Fajr (Dawn) and Maghrib (Sunset) prayers are not to be shortened. Therefore, you must make up the Maghrib prayer in all cases where you shortened it. The permissibility of shortening prayers is conditional upon the journey being lawful.