This error can occur when a user with 'manage training courses' in their profile attempts to edit an existing training course that was created by the GVO Manager.
The user needs to ask the GVO Manager to edit and resave the course and then the user will be able to save the edits. The error is present due to a system change made in December 2020 to split the ability to manage the courses from the ability to mark attendance for others. All courses created after that date do not have this problem.
The change was made based on user feedback.
The error message looks like below.
