I have the Galaxy S6 Edge also. I am having the same issue and it just started yesterday. At one point the phone was really warm and the battery dropped down to 37% in less than an hour. Then I noticed the security alert "Verizon Store Demo Mode" - Medium Risk.
I tried letting the security software remove it, to no avail. Today the threat is still appearing, but the phone is normal temperature and is holding a normal charge.
I'm suspicious of this thing. PLEASE HELP.