Unique weapon not present (possible SPOILER)

In the P4ND0R4 memory cluster, there’s a loot chest just past the train tracks beyond the church. It has that unique laser with Pickle’s voice, I believe. I previously retrieved that weapon with a level 51 Claptrap in TVHM. Went there today with Athena at level 28 in Normal mode, first time ever playing through the Claptastic Voyage DLC with Athena, and the chest was already open and empty.

Successfully retrieved the MORQ with her, as with two other characters in two other game modes (UVHM Jack, TVHM Claptrap). It was there, no problem. Not so much this gun, though. :-/