While playing the first story mission of the season of the hunt, I used Gjallerhorn to clear enemies before reaching the Shrine of Oryx. This resulted in enemies not spawning after a few waves which made it impossible to progress as the mission objective would not update and the walls prohibiting access to the next area were up indefinitely. After using different weapons I managed to complete the mission without any complications. My theory is that the Wolfpack rounds of Gjallerhorn messed with some trigger in the story mission. This worries me as that problem could potentially exist outside of this singular mission. For reference, I used both rocket launcher reserves mods, so I had a total of 9 shots of Gjallerhorn if anybody is trying to replicate it.