Hey Diego, I'm thankful that you were willing to take the time to try and help me, but I felt bad making you do it so I continued looking and found out the problem.
What happens is: I have an object with the Fade behavior (fade in: 0, wait: 0.2, fade out: 0.001) that is also synced thru multiplayer, and it appears that when multiplayer tries to destroy it on peers after it is destroyed on the host, both it and the Fade behavior queue the destruction, making for 2 calls (as you've described) that are causing the exceptions.
On that note, it also seems there isn't a way to disable the Fade behavior in runtime (as in the "time of running", not the runtime object) for me to do it for peers, or am I mistaken?