IAM: better handling of user group default begin on period

Currently when adding a user group to a user in IAM the begins on is set based on the begins on of the user. When the begins on period lies in the future this makes sense. When the begins on lies in the past this is incorrect. I want to be able to see when the group was added to correctly trouble shoot rights issues. 

I would suggest this logic: 

if begins on >= getdate()
then begins on
else getdate()