This has happened in FHM 5 as well, I would have to manually keep going into the draft years to make sure players would not be playing in the WHL, OHL etc. Till they were 24-28. Why is this bug still in the game? Every free agency I see guys 23-24 years of age just get out of the OHL etc. Something is going on here, because these leagues themselves aren't enforcing their players to be done by 20-21..
Like this:
https://imgur.com/a/dPNPVYA