Bump for this issue.
Other blaster-wielding hero/villain emotes do not work as well for the 2nd emote slot, if you have three star cards equipped, in the case of all platforms. (PC, PS4, XONE) Both of Iden's emote slots doesn't work, both of Leia's emote slots reportedly doesn't work. Lando's and Chewbacca's 2nd emote slot doesn't work. Han Solo's, Finn's, and Captain Phasma's 2nd emote slot reportedly doesn't work.
Both emote slots that do work with three star cards equipped for specific heroes/villains: Darth Vader, Darth Maul, Emperor Palpatine, Luke Skywalker, Yoda, and Rey.
Edit: thanks to boomyak on reddit, you have to un-equip two star cards for both emote slots to work, on say, Leia, Iden, Lando, Chewbacca.
https://www.reddit.com/r/StarWarsBattlefront/comments/863v4m/i_know_what_youre_going_to_say/
If you un-equip only one star card, you cannot use the 2nd emote slot on heroes like Iden, Lando, Chewbacca.
Still, this is not a permanent solution and only suitable for, say, Arcade to use the bugged hero emote slots at all right now. Un-equipping two star cards puts you at a disadvantage in multiplayer.