Possibly just other usages of "im Urlaub" enhanced, like "im Urlaub erlebten wir das und das", "im Urlaub hatten wir schönes Wetter" and so on. "In Urlaub" as in presently being there, appears absolutely Mistaken in Upper-Austrian, but I do not understand about the Germans. I have also heard of https://bihlmayermedia-bilder.com/urlaub/wir-sind-im-urlaub/