I am on a mac working in CC 2014. For the last couple of days, when I switch layers, PS changes from the RGB channels to the alpha channel. When I paste from one layer to another, it frequently will paste into the alpha channel. I've been doing working in

I am on a mac working in CC 2014. For the last couple of days, when I switch layers, PS changes from the RGB channels to the alpha channel. When I paste from one layer to another, it frequently will paste into the alpha channel. I've been doing working in PS for many years and have never encountered this issue. Any ideas?