When using Google Chrome, Mozilla Firefox, or Safari upon removing a student's pathway a dialog box will appear asking to confirm the action being taken. Within this dialog box there may be a checkbox with the label "Prevent this page from creating additional dialogs". When checked it disables future dialog boxes from appearing, which in-turn prevents removing of student pathways.
In order to reset the checkbox the web browser will need to be completely closed out and re-opened. Once done you should once again be able to remove students pathways.