Your submission didn't generate a thread on upload - even though threads are no longer used on the new modding discussions system, they are still automatically created to hold info on mapset metadata including the description.
Sometimes this can happen when metadata fields are too long (even if they don't exceed the limits allowed by BSS). Try shortening or removing some of your song title and artist metadata, then update the map to see if a thread is generated. You can change the metadata back at a later stage if this fixes the problem.
If this still doesn't fix the problem, get back to me and I'll see if it can be resolved by deleting and resubmitting the mapset.
