Ok, on a hunch because I can no longer run the outdated M3.3 (PHP issue with needing to develop for M3.7), because you were running the wrong version of the Grid format then when the course was created then the 'numsections' was not created for the given course. Switching between course formats normally fixes things, or perhaps does in newer versions. So... this is a theoretical fix based on knowledge, thus backup your Moodle / courses / databases first - and if you have an identical test system, even better:
- Note down the course id (id bit in the url when viewing a course) for all affected courses and what format they are using.
- Open up the database and find the 'course_format_options' table.
- Make an entry for each 'course' id with the format of the 'format', section id of 0, name of 'numsections' and a value of the number of sections you want on the given course. If you have other courses that are fine then look for examples in the same table.
- Purge all caches.