Solved PlayerInteractEvent fires twice?

I'm having an issue where an event handler for the PlayerInteractEvent fires twice on a single interaction.

Here's my code:


Here's what happens when I right click a block once:


I've checked all things I thought of that could be causing the issue (Accidentally calling onBlockUse from somewhere else, registering events twice, creating 2 objects of the event handler class) and none of these are the case.

I'm using CraftBukkit version git-Bukkit-753a8e7 (MC: 1.12) on my test/development server.

Is there some oversight on my end or is this a bug?

I'm using this event to send a message to the player clicking the block, and it's kind of jarring to have two identical messages pop up when I only right clicked once.

 

Yup, there is. I was under the impression that it would only fire once and I'd get the item in hand/offhand myself.
Anyways, I added an additional check for the hand, and now I only get one message. Thanks!