I didn't understand exactly when it happens, but it is definitely a bug. Once reached negatives, one can still safely click next and last buttons to navigate, but the schedule is shown as empty.
Thanks for the report! If you're able to reproduce the issue with a particular set of courses or steps, please add a comment so we can look into this further.
I didn't understand exactly when it happens, but it is definitely a bug. Once reached negatives, one can still safely click next and last buttons to navigate, but the schedule is shown as empty.