There is an issue with assigning schedules in promotion/relegation leagues and tournaments.
When assigning schedules for promotion/relegation leagues and tournaments, the system ignores the loaded schedules and arbitrarily generates new ones. I created a schedule in the ILN_BGY_G110_T12 format and placed it in the data/schedule folder. When the league was created, it successfully loaded the schedule file and generated the league schedule correctly. However, it fails to load the schedule next preseason.
The suspected cause is as follows:
According to the OOTP Online Manual's "How Schedules Work" section, OOTP randomizes team matchups every year. I assume this randomization occurs when the offseason begins. However, promotion and relegation occur during the offseason. This seems to cause an error while loading the schedule because teams have moved due to promotion and relegation. Although I don't know the exact internal logic, I think the problem could be solved by performing the randomization immediately before schedule generation.