I will fix this by using a script that deletes the previous users login keychain information on login. A new keychain is created each time a user logs in and then is deleted when they login again, thus avoiding the keychain sync issue.
The reasoning for that decision is here: http://technology.siprep.org/deleting-keychains-at-user-logout/
I will either use a logout hook, which is deprecated by apple but still usable (and very simple to implement): http://www.amsys.co.uk/2015/02/delete-keychains-logout/?nabe=6486817002487808:0
or I will use Offest: https://github.com/aysiu/offset