Multi-weapon bug

So I was trying to make a multi weapon from resurgir daggers and resurgir saber and it just said "An error has occurred" and then my game crashed. It happened 3 times and then I couldn't reconnect to the game and had to do a restart of my console.

Now I'm scared to try and make any kind of multi weapon. Are they bugged or something?

"UPDATE"

Okay so whatever is going on is apperently only affecting 4 star weapons. I can multi-weapons from 1 star weapons but not from 4 star ones.

Your bug is not a multi-weapon bug as you have not created it, but rather an Item Lab bug that you are experiencing. See what happens after a File Check.