Current behavior:
Currently, Group Description has a limit of 255 characters, while AD has a limit of 1024 characters:

• https://social.technet.microsoft.com/Forums/sharepoint/en-US/c031d126-1bc6-4d72-a3b2-fc9d7aaeb488/character-limit-in-description-attribure?forum=winserverDS

Suggestion:
Increase the character limit of the group description to 1024 to accommodate AD

Reason for suggestion:
Currently if group description of a group inside a user directory is more than 255, the synchronization to that user directory will fail, described here

• https://jira.atlassian.com/browse/CWD-2559