If you use the hold the skill Big Blast on the shellshot blunderbuss with 0 ammo it will still charge up and glow as if it had a shot to fire, but will still fire nothing. The head of the cannon will also glow when doing this until filling up the cannon again.
Steps to Reproduce
1. Hold the skill big blast with 0 ammo and notice how the shellshot blunderbuss will still glow, and will cause the head of the cannon to glow.
A developer has marked this issue as fixed. This means that the issue has been addressed in the current development build and will likely be in the next update.