Our LTI is dependent on several custom variables. Today we noticed that the custom_canvas_user_id changed for a user. On May 20, 2016 she used our LTI for the first time and the custom_canvas_user_id param came across as 72070000000000176. Today and it came across as 176 which caused us to create a duplicate account.
What's going on here? We were under the assumption the custom_canvas_user_id is a globally unique field that never changes.