Character Experience Passover

You know how when your playing on one character and you pass another character you were playing? That happens a lot. But the thing is is that the "experience" in the story mode passes over to the other characters so I can fight The Ruin with a character I just made.

If you didn't understand what I just said then this is what just happened to me:
I make a character (Lets call the character Bob) and play with a friend until we get the the Hylotl mission. When my frined isn't on I play a different character ( Lets say Billy) and beat the Kluex Avatar. I then go back to Bob to check if I got the mission to go to the Grand Pagoda Library, but when I get to The Ark I notice that I somehow already have the Avian artifact. I only played on the Billy character to do the Avian mission and nothing else.

Is this a glitch (Heh, puns.) or something I can turn off? Or do I just have to deal with this?
Any help is appreciated.

P.S.
For the "Create a Character" things on the site, do you think there should be a Novakid as an option?

 

Thanks, but am I able to transfer characters to a different universe or get rid of the extra mission data?

 

Ok, thanks