CKEditor tabber shows tabs to the right on the screen when logged in as admin
In case anyone else has the same problem I will answer my own question. I found the answer to my problem in this issue for the same module: https://www.drupal.org/node/2774763
The problem was not exactly the same to begin with, but the solution was the same. The variable tabIndex needed to be placed within the function, not outside as a global. Problem solved.