Yes, after removing the nvidia proprietary driver and replacing it with nouveau I can still reproduce the issue.
** Changed in: xorg-server (Ubuntu) Status: Incomplete => New -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg-server in Ubuntu. https://bugs.launchpad.net/bugs/1585329 Title: Sometimes a black rectangle appears briefly under the mouse cursor To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/1585329/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp