During the Endwalker MSQ, Strange Bedfellows, Urianger can be see during the cutscene and outside the cutscene at Tertium (on the back train cart) with a Grimoire on him in stead of his Astro weapon. Immediately following, in a cutscene and as an interactable NPC on the open world he has his Astro weapon back.

I did not think to grab a screen shot on the open world but I have a screen shot during the CS. Just not sure how to post it here.

I'm sure a replay or even a video on YouTube has the footage for this quest.