For one user when access to My Home, Moodle return error:

Found more than one record in fetch() !

More information about this error

Stack trace:
line 435 of /lib/setuplib.php: moodle_exception thrown
line 146 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 947 of /lib/grade/grade_item.php: call to grade_item::fetch()
line 352 of /lib/gradelib.php: call to grade_item::fetch_course_item()
line 3707 of /mod/assignment/lib.php: call to grade_get_grades()
line 847 of /course/lib.php: call to assignment_print_overview()
line 107 of /blocks/course_overview/block_course_overview.php: call to print_overview()
line 280 of /blocks/moodleblock.class.php: call to block_course_overview->get_content()
line 232 of /blocks/moodleblock.class.php: call to block_base->formatted_contents()
line 934 of /lib/blocklib.php: call to block_base->get_content_for_output()
line 986 of /lib/blocklib.php: call to block_manager->create_block_contents()
line 311 of /lib/blocklib.php: call to block_manager->ensure_content_created()
line 957 of /lib/outputrenderers.php: call to block_manager->get_content_for_region()
line 150 of /my/index.php: call to core_renderer->blocks_for_region()