Is it permissible for a person who resides in the town of Mu'tah and works in Petra (160 km) to combine and shorten prayers, then return to attend a training course in Mu'tah?

A traveler is not permitted to shorten prayers (qasr) in their hometown (Mu'tah in this case) immediately upon entering it, even if they do not intend to reside there. This is because jurists hold that travel ceases upon entering one's original homeland. Imam An-Nawawi mentioned that the madhhab (school of thought), and what the majority of scholars have definitively stated, is that a traveler becomes a resident upon entering their homeland. So, how then can they still be considered a traveler at that point?