Got the same problem on 16.04. It seems the issue was caused by Unity upgrade to 7.4.5. I manually downgraded it to 7.4.0 and the issue was gone:
sudo apt-get install unity=7.4.0+16.04.20160415-0ubuntu1 libunity- core-6.0-9=7.4.0+16.04.20160415-0ubuntu1 unity- services=7.4.0+16.04.20160415-0ubuntu1 unity- schemas=7.4.0+16.04.20160415-0ubuntu1 compiz- core=1:0.9.12.2+16.04.20160415-0ubuntu1 compiz=1:0.9.12.2+16.04.20160415-0ubuntu1 compiz-plugins- default=1:0.9.12.2+16.04.20160415-0ubuntu1 compiz- gnome=1:0.9.12.2+16.04.20160415-0ubuntu1 libcompizconfig0=1:0.9.12.2+16.04.20160415-0ubuntu1 libdecoration0=1:0.9.12.2+16.04.20160415-0ubuntu1 -- You received this bug notification because you are a member of compiz packagers, which is subscribed to compiz in Ubuntu. https://bugs.launchpad.net/bugs/1689356 Title: UI scale being reset to 1 everytime when display sleeps for a while To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/1689356/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~compiz Post to : compiz@lists.launchpad.net Unsubscribe : https://launchpad.net/~compiz More help : https://help.launchpad.net/ListHelp