That's because you have enabled secure folder, looks to be an issue with google now launcher if you have secure folder enabled. Someone else mentioned this issue and I said it was not happening to me, but spoke too soon and got the same issue later. I had to uninstall secure folder to get back the apps in the drawer if using google now launcher.
FYI - TouchWiz launcher was fine with secure folder installed so you can use that if you want secure folder, haven't checked with Nova.