attempting to create a plain workshop with default settings gets me the following :

Found more than one record in fetch() !

More information about this error
Stack trace:

• line 359 of /lib/setuplib.php: moodle_exception thrown
• line 142 of /lib/grade/grade_object.php: call to print_error()
• line 316 of /lib/grade/grade_item.php: call to grade_object::fetch_helper()
• line 2595 of /course/lib.php: call to grade_item::fetch()
• line 442 of /course/modedit.php: call to set_coursemodule_visible()

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apparently something about it trying to be set as visible?