bag_aware and var interaction
Some of vars in files extending bag_aware.gd need to be local. Bag_aware is a dispatcher of vars but some of them need to be local. In that case, the execution went wrong and show the message "Invalid set index...". Verify if the var in question is in a file that extends bag_aware.gd and if its call is self.###. You will need to delete the self.
and declare the var in the top of the file
Edited by Killian Gricourt