The auto crossbow would just work like a regular crossbow would

To be clear: Our auto crossbow is not automatic in the way that a gun is. How it works is that the charging speed gets faster and faster the more you shoot in a given amount of time, ending up nearly automatic by the end. You will always need a click to charge it and a click to fire it, the only difference is how long you need to hold down the first click.

Given this explanation, does this match what you are seeing in game?

May be related: #215

Closing, because #215 was fixed and I can see no other reason why the auto crossbow would not be working without more details.